Description of problem:
When trying to run Pungi to create install media, it fails with yum.Errors.GroupsError: No Groups Available in any repository

Version-Release number of selected component (if applicable):
pungi-2.5-2.fc15.noarch

How reproducible:
100%

Steps to Reproduce:
1. Install pungi
2. Run pungi
  
Actual results:
[root@t61dora F15custom]# pungi -c /var/www/html/fedora-desktop.cfg --destdir=/tmp/spins/F15custom --name Fedora Tweaked --ver 15 --nosource --force
WARNING: SELinux is enforcing.  This may lead to a compose with selinux disabled.
Consider running with setenforce 0.
Warning: Reusing existing destination directory.
Pungi:INFO: Getting sacks for arches ['athlon', 'i586', 'i486', 'noarch', 'i386', 'i686', 'src']
Traceback (most recent call last):
  File "/usr/bin/pungi", line 214, in <module>
    main()
  File "/usr/bin/pungi", line 88, in main
    mypungi.getPackageObjects()
  File "/usr/lib/python2.7/site-packages/pypungi/__init__.py", line 412, in getPackageObjects
    searchlist.extend(self.getPackagesFromGroup(group))
  File "/usr/lib/python2.7/site-packages/pypungi/__init__.py", line 306, in getPackagesFromGroup
    if not self.ayum.comps.has_group(group.name):
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 882, in <lambda>
    comps = property(fget=lambda self: self._getGroups(),
  File "/usr/lib/python2.7/site-packages/yum/__init__.py", line 805, in _getGroups
    raise Errors.GroupsError, _('No Groups Available in any repository')
yum.Errors.GroupsError: No Groups Available in any repository

Expected results:
Pungi runs and completes as expected

Additional info:
Tried a yum clean all followed by yum grouplist followed by pungi again and still failed.
Tried with SELinux in permissive mode, still failed.
Tried with multiple kickstarts, all failed.