software-properties-gtk crashed with ValueError in run(): <aptsources.sourceslist.SourceEntry object at 0x20bb750> is not in list

[Lotd]

Add a natty ppa, im my case sudo apt-add-repository ppa:bisigi/ppa, then open the Software Sources, modify the package (oneric to natty) and hit OK.
it should either hang or crash.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: software-properties-gtk 0.81.9
ProcVersionSignature: Ubuntu 3.0.0-9.15-generic 3.0.3
Uname: Linux 3.0.0-9-generic x86_64
NonfreeKernelModules: fglrx
Architecture: amd64
Date: Wed Aug 31 22:58:32 2011
ExecutablePath: /usr/bin/software-properties-gtk
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110831)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/software-properties-gtk
ProcEnviron:
 PATH=(custom, no user)
 LANG=da_DK.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/software-properties-gtk']
SourcePackage: software-properties
Title: software-properties-gtk crashed with ValueError in run(): <aptsources.sourceslist.SourceEntry object at 0x20bb750> is not in list
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[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 #829286, 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.