Yum FC6 error

[david walcroft]

I upgraded from FC5 > FC6 with very few problems,I have two which I 
don't know how to fix:-

[david at reddwarf ~]$ sudo yum -y update
Loading "installonlyn" plugin
Traceback (most recent call last):
   File "/usr/bin/yum", line 29, in ?
     yummain.main(sys.argv[1:])
   File "/usr/share/yum-cli/yummain.py", line 85, in main
     base.getOptionsConfig(args)
   File "/usr/share/yum-cli/cli.py", line 199, in getOptionsConfig
     errorlevel=opts.errorlevel)
   File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 123, in 
doConfigSetup
     startupconf.pluginconfpath)
   File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 252, in 
doPluginSetup
     plugin_types, confpath)
   File "/usr/lib/python2.4/site-packages/yum/plugins.py", line 129, in 
__init__
     self._importplugins(types)
   File "/usr/lib/python2.4/site-packages/yum/plugins.py", line 170, in 
_importplugins
     self._loadplugin(modulefile, types)
   File "/usr/lib/python2.4/site-packages/yum/plugins.py", line 186, in 
_loadplugin
     module = imp.load_module(modname, fp, pathname, description)
   File "/usr/lib/yum-plugins/stablemirror.py", line 140, in ?
     from repomd import repoMDObject, mdErrors
ImportError: No module named repomd

And Yumex will not start,how do I debug as to why it's not.

Thanks  david