update-manager crashed with ValueError in ./xorg_fix_proprietary.py: _system not initialized

[AJ]

crash on first logon after upgrade frmo 11.10

ProblemType: Crash
Date: Fri Mar 2 12:05:16 2012
ExecutablePath: /usr/bin/update-manager
ExecutableTimestamp: 1326448883
InterpreterPath: /usr/bin/python2.7
ProcCmdline: /usr/bin/python ./xorg_fix_proprietary.py
ProcCwd: /tmp/update-manager-PLHaBy
ProcEnviron:
 LANG=en_AU.utf8
 TERM=xterm
 LANGUAGE=en_AU:en
 PATH=(custom, user)
 SHELL=/bin/zsh
PythonArgs: ['/usr/bin/update-manager']
Traceback:
 Traceback (most recent call last):
   File "./xorg_fix_proprietary.py", line 160, in <module>
     if ver and apt_pkg.VersionCompare(ver, "2:1.5.0") > 0:
 ValueError: _system not initialized
UserGroups: