Ubuntu restricted extras cause crash

[grahams1]

MESSAGE RECEIVED:
"
An unhandleable error occured

There seems to be a programming error in aptdaemon, the software that allows you to install/remove software and to perform other tasks related to package management. Please report this error at http://launchpad.net/aptdaemon/+filebug and retry.

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 779, in simulate
    return self._simulate_helper(trans, status_path)
  File "/usr/lib/python2.6/dist-packages/aptdaemon/worker.py", line 958, in _simulate_helper
    return depends, status, self._cache.required_download, \An unhandleable error occured
  File "/usr/lib/python2.6/dist-packages/apt/cache.py", line 218, in required_download
    pm.get_archives(fetcher, self._list, self._records)
SystemError: E:I wasn't able to locate file for the ubuntu-restricted-addons package. This might mean you need to manually fix this package.
"