Same problem when installing xfce-desktop-environment:

...
  Verifying  : xfwm4-themes-4.10.0-3.fc19.noarch                                                                                                                                                           125/127 
  Verifying  : xfwm4-theme-nodoka-0.2-5.fc19.noarch                                                                                                                                                        126/127 
  Verifying  : catfish-0.4.0.2-2.fc19.1.noarch                                                                                                                                                             127/127 
Traceback (most recent call last):
  File "/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 316, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 219, in main
    return_code = base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 697, in doTransaction
    resultobject = self.runTransaction(cb=cb)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1763, in runTransaction
    self.igroups.save()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 148, in save
    self._write_grp_grps()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 175, in _write_grp_grps
    if self.groups[grpname].environment == evgrp.evgid:
KeyError: 'xfce-extra-plugins'
[mfabian@Fedora-19-Alpha-TC2-x86_64-DVD ~]$

[mfabian@Fedora-19-Alpha-TC2-x86_64-DVD ~]$ LANG=en_US.UTF-8 sudo yum groupinstall xfce-desktop-environment kde-desktop-environment
[sudo] password for mfabian: 
Loaded plugins: langpacks, refresh-packagekit
Warning: environment xfce-desktop-environment does not exist.
Warning: environment kde-desktop-environment does not exist.
No packages in any requested group available to install or update
[mfabian@Fedora-19-Alpha-TC2-x86_64-DVD ~]$

Also same problem with lxde-desktop-enviroment:

...
  Verifying  : lxappearance-obconf-0.2.0-2.fc19.x86_64                                                                                                                                                       34/36 
  Verifying  : xorg-x11-resutils-7.5-7.fc19.x86_64                                                                                                                                                           35/36 
  Verifying  : perl-File-MimeInfo-0.16-4.fc19.noarch                                                                                                                                                         36/36 
Traceback (most recent call last):
  File "/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 316, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 219, in main
    return_code = base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 697, in doTransaction
    resultobject = self.runTransaction(cb=cb)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1763, in runTransaction
    self.igroups.save()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 148, in save
    self._write_grp_grps()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 175, in _write_grp_grps
    if self.groups[grpname].environment == evgrp.evgid:
KeyError: 'lxde-apps'
[mfabian@Fedora-19-Alpha-TC2-x86_64-DVD ~]$ LANG=en_US.UTF-8 sudo yum groupinstall lxde-desktop-environment 
Loaded plugins: langpacks, refresh-packagekit
Warning: environment lxde-desktop-environment does not exist.
No packages in any requested group available to install or update
[mfabian@Fedora-19-Alpha-TC2-x86_64-DVD ~]$

Created attachment 717708 [details]
/var/log/yum.log

Reassigning to James, as this seems to be related to the code in yum groups that he changed lately.

Created attachment 732179 [details]
console output of "yum groupinstall ¡Xfce desktop' " on a minimal F19a TC5 updared guest

Me too, doing a groupinstall 'Xfce Desktop' from a minimal install.
F19a TC5, updated.

  Verifying  : paps-0.6.8-24.fc19.x86_64                       842/844 
  Verifying  : 1:NetworkManager-vpnc-.9.3.997-4.fc19.x86_64    843/844 
  Verifying  : libhangul-0.1.0-6.fc19.x86_64                   844/844 
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 316, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 219, in main
    return_code = base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 697, in doTransaction
    resultobject = self.runTransaction(cb=cb)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1763, in runTransaction
    self.igroups.save()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 148, in save
    self._write_grp_grps()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 175, in _write_grp_grps
    if self.groups[grpname].environment == evgrp.evgid:
KeyError: 'xfce-extra-plugins'
[root@localhost ~]

I tested these, from a minimal-only F19a TC5 (updated) installation:

* Xfce Destkop

See previous comment.

* Web Server

Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 316, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 219, in main
    return_code = base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 697, in doTransaction
    resultobject = self.runTransaction(cb=cb)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1763, in runTransaction
    self.igroups.save()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 148, in save
    self._write_grp_grps()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 175, in _write_grp_grps
    if self.groups[grpname].environment == evgrp.evgid:
KeyError: 'haproxy'

* Infrastructure Server

Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 316, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 219, in main
    return_code = base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 697, in doTransaction
    resultobject = self.runTransaction(cb=cb)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1763, in runTransaction
    self.igroups.save()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 148, in save
    self._write_grp_grps()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 175, in _write_grp_grps
    if self.groups[grpname].environment == evgrp.evgid:
KeyError: 'dns-server'

*** Bug 949125 has been marked as a duplicate of this bug. ***

Description of problem:
I've installed KDE desktop with yum groupinstall "KDE Plasma Workspaces" --skip-broken
(--skip-broken because there are some libreport dep issues on PPC atm.)
yum downloaded, installed and verified all packages, but after verifying the last package I got this error

Version-Release number of selected component:
yum-3.4.3-81.fc19

Additional info:
cmdline:        /usr/bin/python /bin/yum groupinstall 'KDE Plasma Workspaces' --skip-broken --nogpg
executable:     /bin/yum
kernel:         3.9.0-0.rc4.git0.1.fc19.ppc64p7
runlevel:       unknown
uid:            0
ureports_counter: 1

Truncated backtrace:
igroups.py:175:_write_grp_grps:KeyError: 'kde-apps'

Traceback (most recent call last):
  File "/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 316, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 219, in main
    return_code = base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 697, in doTransaction
    resultobject = self.runTransaction(cb=cb)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 1763, in runTransaction
    self.igroups.save()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 148, in save
    self._write_grp_grps()
  File "/usr/lib/python2.7/site-packages/yum/igroups.py", line 175, in _write_grp_grps
    if self.groups[grpname].environment == evgrp.evgid:
KeyError: 'kde-apps'

Local variables in innermost frame:
self: <yum.igroups.InstalledGroups object at 0x3fffaf8c80d0>
grpname: 'kde-apps'
fo: <open file '/var/lib/yum/groups/environment.tmp', mode 'w' at 0x1003376fc90>
evgrp: <yum.igroups.InstalledEnvironment object at 0x100307fcf10>

*** Bug 951078 has been marked as a duplicate of this bug. ***

 This should be fixed in:

-86 which went into rawhide and f19 yesterday.

Discussed at 2013-04-24 blocker review meeting: http://meetbot.fedoraproject.org/fedora-blocker-review/2013-04-24/f19beta-blocker-review-1.2013-04-24-16.00.log.txt . Rejected as a Beta blocker: it doesn't seem that this bug likely affects the installation environment, and anyway, it doesn't seem to prevent the operation actually succeeding.

The bug can be re-proposed if it turns out to be worse than it seemed to us in the meeting.

*** Bug 960406 has been marked as a duplicate of this bug. ***

*** Bug 954118 has been marked as a duplicate of this bug. ***

I does still happen.

Install F19b TC3, do a yum update and then a groupinstall KDE Plasma Workspaces.

*** Bug 962044 has been marked as a duplicate of this bug. ***

I does still happen. (F19b RC4)

Workaround: 

Edit /etc/yum.conf and set 'group_command=compat'

The feature "Yum Groups as Objects" is marked as 100% completed.
To workaround the issue described in this bug-report, one has 
to revert the feature back.

Also yum.conf man page is outdated and the new default setting 
"group_command=objects" is not described there.

While i do agree with comment #12, the fact that one needs to 
revert a feature which is marked as 100% complete should not be
overlooked. 

Please note that not just 'group install' has issues, 'group remove'
and 'group list' also have their own, see below.

As test below indicate, it seems to happen with the "first time" a
'yum groupinstall' performed by the user (default yum.conf).
Subsequent 'yum groupinstall' executions have no issues.

The workaround fixes the "first time" 'yum groupinstall' exception.

It is still not a blocker nor FE, but if not fixed
the yum.conf settings "group_command=compat" should be the default.

An initial 'yum update' seems to inhibit the 'yum groupinstall' issue
from happen, at least it these tests. But does not help with the other
issues.

Currently, at least to me, it looks like setting the yum.conf setting
"group_command=compat" is a safer move.

TESTED MEDIA:        F19b RC4 x86_64
VERSION: yum.noarch  3.4.3-91.fc19

TST#1: (FNEXT-TST3)
* Install BE: Minimal Add-ONs: None
* No previous 'yum update' was executed
* Default yum.conf settings
* yum groupinstall 'LXDE Desktop'          >>> RESULT: ERROR (this bug-report issue)
* yum groupinstall virtualization          >>> RESULT: OK
* yum groupinstall 'KDE Plasma Workspaces' >>> RESULT: OK

* yum group remove virtualization   >>>  RESULT: ERROR (this or bug-prima)
* yum group remove 'LXDE Desktop    >>>  RESULT: ERROR: no packages to remove from groups

* yum group list    >>> RESULT: NEITHER 'Installed environment groups' NOT 'Installed groups' are shown (!)

TST#2: (FNEXT-TST4)
* Install BE: Minimal Add-ONs: None
* No previous 'yum update' was executed
* Default yum.conf settings
* yum groupinstall 'LXDE Desktop'          >>> RESULT: ERROR (this bug-report issue)
* Change yum.conf, set 'group_command=compat'
* yum groupinstall virtualization          >>> RESULT: OK
* yum groupinstall 'KDE Plasma Workspaces' >>> RESULT: OK

* yum group remove virtualization   >>>  RESULT: OK
* yum group remove 'LXDE Desktop    >>>  RESULT: OK?, BUT: 'systemd', 'yum' are declared as protected

* yum group list    >>> RESULT: Both 'Installed environment groups' and 'Installed groups' are shown.

TST#3: (FNEXT-TST1)
* Install BE: Minimal Add-ONs: None
* No previous 'yum update' was executed
* Change yum.conf, set 'group_command=compat'
* yum groupinstall 'LXDE Desktop'          >>> RESULT: OK
* yum groupinstall virtualization          >>> RESULT: OK
* yum groupinstall 'KDE Plasma Workspaces' >>> RESULT: OK

* yum group remove virtualization   >>>  RESULT: OK
* yum group remove 'LXDE Desktop    >>>  RESULT: OK?, BUT: 'systemd', 'yum' are declared as protected

* yum group list    >>> RESULT: Both 'Installed environment groups' and 'Installed groups' are shown.

TST#4: (FNEXT-TST6)
* Install BE: Minimal Add-ONs: None
* Update the system, perform a 'yum update' before the test
* Default yum.conf settings
* yum groupinstall 'LXDE Desktop'          >>> RESULT: OK
* yum groupinstall virtualization          >>> RESULT: OK
* yum groupinstall 'KDE Plasma Workspaces' >>> RESULT: OK

* yum group remove virtualization   >>>  RESULT: RESULT: ERROR (this or bug-prima)
* yum group remove 'LXDE Desktop'   >>>  RESULT: ERROR: no packages to remove from groups

* yum group list    >>> RESULT: NEITHER 'Installed environment groups' NOT 'Installed groups' are shown (!)

FROM: http://fedoraproject.org/wiki/Releases/19/FeatureList

Name:          Yum Groups as Objects
Completition:  100%
Description:   Change the default yum configuration from group_command=compat to group_command=objects.
Updated:       2013-05-07

FROM: http://fedoraproject.org/wiki/Features/YumGroupsAsObjects

Contingency Plan: 
 We can change the configuration default back to compat. 
 
FROM: '# man yum.conf'

group_command List of the following: simple, compat, objects. Tells yum what
to do for group install/upgrade/remove commands.

  Simple acts like you did yum group cmd $(repoquery --group --list group), 
  so it is vrery easy to reason about what will happen. Alas. this is often 
  not what people want to happen.

  Compat. works much like simple, except that when you run "group upgrade" 
  it actually runs "group install" (this means that you get any new packages
  added to the group, but you also get packages added that were there before 
  and you didn't want).

  Objects makes groups act like a real object, separate from the packages 
  they contain. Yum keeps track of the groups you have installed, so 
  "group upgrade" will install new packages for the group but not install 
  old ones. It also knows about group members that are installed but weren't
  installed as part of the group, and won't remove those on "group remove". 
  Running "yum upgrade" will also run "yum group upgrade" (thus. adding new 
  packages for all groups).

  Default is: compat

the "bug-prima", from TST#1: (FNEXT-TST3)

> * yum group remove virtualization   >>>  RESULT: ERROR (this or bug-prima)

# yum group remove virtualization
Loaded plugins: langpacks, refresh-packagekit
No environment named virtualization exists
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 316, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 126, in main
    result, resultmsgs = base.doCommands()
  File "/usr/share/yum-cli/cli.py", line 522, in doCommands
    return self.yum_cli_commands[self.basecmd].doCommand(self, self.basecmd, self.extcmds)
  File "/usr/share/yum-cli/yumcommands.py", line 1047, in doCommand
    return base.removeGroups(extcmds)
  File "/usr/share/yum-cli/cli.py", line 1961, in removeGroups
    txmbrs = self.groupRemove(group.groupid)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 3566, in groupRemove
    igroup_data = self._groupInstalledData(thisgroup)
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 3351, in _groupInstalledData
    for pkg_name in set(group.packages + list(pkg_names)):
AttributeError: 'InstalledGroup' object has no attribute 'packages'

I also noticed that a 'yum group list' no longer lists the  'Installed environment groups'
nor the 'Installed groups'. (with the default yum.conf).

So further 'yum group remove' fails beacuse they are 'not' installed. 

Changing yum.conf setting 'group_command=compat' makes 'group list' work again.

The issue reported in the latest comment is a different one, there is already a bug for that - closing as duplicate of bug 955236.

*** This bug has been marked as a duplicate of bug 955236 ***

@Jan Zeleny

I don't consider the original bug-report closed (fixed). 
I do agree that this bug-report's comment #20 is bug 955236's comment 6, but this bug-report should not be closed at the moment, at least i don't think so.

What i found with comment #18 is that there are issues with 'group install' 'group remove' and 'group list'. All of then can be solved by reverting back the feature "Yum Groups as Objects" by setting 'group_command=compat' in yum.conf.

I think it is better keeping them separate for the moment.