Description of problem:
# yum -y remove sysstat
Loaded plugins: rhnplugin
Setting up Remove Process
Resolving Dependencies
--> Running transaction check
---> Package sysstat.x86_64 0:9.0.4-15.el6 will be erased
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================================================================================================================================================
 Package                                          Arch                                            Version                                                Repository                                        Size
================================================================================================================================================================================================================
Removing:
 sysstat                                          x86_64                                          9.0.4-15.el6                                           @rhel61                                          806 k

Transaction Summary
================================================================================================================================================================================================================
Remove        1 Package(s)

Installed size: 806 k
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing    : sysstat-9.0.4-15.el6.x86_64                                                                                                                                                                  1/1 
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 267, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 203, in main
    return_code = base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 580, in doTransaction
    resultobject = self.runTransaction(cb=cb)
  File "/usr/lib/python2.6/site-packages/yum/__init__.py", line 1495, in runTransaction
    self.plugins.run('posttrans')
  File "/usr/lib/python2.6/site-packages/yum/plugins.py", line 184, in run
    func(conduitcls(self, self.base, conf, **kwargs))
  File "/usr/share/yum-plugins/rhnplugin.py", line 190, in posttrans_hook
    rhnPackageInfo.updatePackageProfile()
  File "/usr/share/rhn/up2date_client/rhnPackageInfo.py", line 28, in updatePackageProfile
    s.registration.update_packages(up2dateAuth.getSystemId(), packages)
  File "/usr/share/rhn/up2date_client/rhnserver.py", line 50, in __call__
    return rpcServer.doCall(method, *args, **kwargs)
  File "/usr/share/rhn/up2date_client/rpcServer.py", line 204, in doCall
    ret = method(*args, **kwargs)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 1199, in __call__
    return self.__send(self.__name, args)
  File "/usr/share/rhn/up2date_client/rpcServer.py", line 39, in _request1
    ret = self._request(methodname, params)
  File "/usr/lib/python2.6/site-packages/rhn/rpclib.py", line 379, in _request
    request = self._req_body(self._strip_characters(params), methodname)
  File "/usr/lib/python2.6/site-packages/rhn/rpclib.py", line 234, in _req_body
    return xmlrpclib.dumps(params, methodname, encoding=self._encoding)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 1132, in dumps
    data = m.dumps(params)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 677, in dumps
    dump(v, write)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 699, in __dump
    f(self, value, write)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 703, in dump_nil
    raise TypeError, "cannot marshal None unless allow_none is enabled"
TypeError: cannot marshal None unless allow_none is enabled

Version-Release number of selected component (if applicable):
yum-3.2.29-3.el6.noarch
python-2.6.6-6.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Install latest RHEL6.1 tree
2. yum -y remove syststat
  
Actual results:
Traceback, but package is removed

Expected results:
No traceback

Additional info: