Description of problem:
After installing the rpm package for the rpmfusion repo, i got an update shown by packagekit, about the repo configuration.
Installing the updates failed, because the signing key could not be imported by packagekit. Packagekit showed a errormessage dialog with traceback ( added at the end).
This happend nearly 5 times.

Solution:
updated / imported key via terminal

yum update

Version-Release number of selected component (if applicable):
Name        : PackageKit
Arch        : i686
Version     : 0.6.6
Release     : 1.fc13


How reproducible:
not sure. just testet on 1 machine.

Steps to Reproduce:
1. install repo rpm via:
 rpm -Uvh http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm
2.
try updating with the packagekit frontend
3. aborting update process after authorizing the import key via root password 
  
Actual results:
Errormessage Shown

Expected results:
importing key and updating the package

Additional info:
Error message shown was:

failed to install signature: Traceback (most recent call last):
  File "/usr/share/PackageKit/helpers/yum/yumBackend.py", line 2926, in install_signature
    self.yumbase.getKeyForPackage(pkg, askcb = lambda x, y, z: True)
  File "/usr/lib/python2.6/site-packages/yum/__init__.py", line 4329, in getKeyForPackage
    result = ts.pgpImportPubkey(misc.procgpgkey(info['raw_key']))
  File "/usr/lib/python2.6/site-packages/rpmUtils/transaction.py", line 59, in __getattr__
    return self.getMethod(attr)
  File "/usr/lib/python2.6/site-packages/rpmUtils/transaction.py", line 69, in getMethod
    return getattr(self.ts, method)
AttributeError: 'NoneType' object has no attribute 'pgpImportPubkey'