software-properties-gtk crashed with AttributeError in remove_source(): 'NoneType' object has no attribute 'file'

[trebor271074]

help?

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: software-properties-gtk 0.81.2
ProcVersionSignature: Ubuntu 3.0.0-6.7-generic 3.0.0-rc7
Uname: Linux 3.0.0-6-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Mon Jul 25 10:45:31 2011
ExecutablePath: /usr/bin/software-properties-gtk
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110724)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/software-properties-gtk -n -t 65011717
ProcEnviron:
 PATH=(custom, no user)
 LANG=ro_RO.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/software-properties-gtk', '-n', '-t', '65011717']
SourcePackage: software-properties
Title: software-properties-gtk crashed with AttributeError in remove_source(): 'NoneType' object has no attribute 'file'
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make Ubuntu better. This particular crash has already been reported and is a duplicate of bug #820150, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.