software-center-gtk3 crashed with AttributeError in preparse(): 'NoneType' object has no attribute 'lower'

[Luke Graybill]

I was trying to install the google-chrome dev channel deb file, and the Software Center opened, showed a spinning dial for a few minutes, then died.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: software-center 4.1.21
ProcVersionSignature: Ubuntu 3.0.0-10.16-generic 3.0.4
Uname: Linux 3.0.0-10-generic x86_64
Architecture: amd64
Date: Wed Sep 7 00:10:28 2011
ExecutablePath: /usr/share/software-center/software-center-gtk3
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64+mac (20110901)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/software-center-gtk3 /home/username/Downloads/google-chrome-unstable_current_i386.deb
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/software-center-gtk3', '/home/username/Downloads/google-chrome-unstable_current_i386.deb']
SoftwareCenterLog:
 2011-09-07 00:09:06,759 - softwarecenter.ui.gtk3.em - INFO - EM's: 17 15 21
 2011-09-07 00:09:09,543 - softwarecenter.fixme - WARNING - logs to the root logger: '('/usr/share/software-center/softwarecenter/db/database.py', 175, 'open')'
 2011-09-07 00:09:09,543 - root - WARNING - failed to add sca db Couldn't stat '/home/luke/.cache/software-center/software-center-agent.db' (No such file or directory)
 2011-09-07 00:09:10,071 - softwarecenter.backend.reviews - WARNING - Could not get usefulness from server, no username in config file
 2011-09-07 00:09:37,114 - softwarecenter.ui.gtk3.app - INFO - software-center-agent finished with status 1
SourcePackage: software-center
Title: software-center-gtk3 crashed with AttributeError in preparse(): 'NoneType' object has no attribute 'lower'
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 #839113, 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.