software-center crashed with AttributeError in _decode_value(): 'NoneType' object has no attribute 'decode'

[Traista Eugen]

software center crashes when i try to install google chrome beta amd64 on ubuntu 12.04

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: software-center 5.1.4
ProcVersionSignature: Ubuntu 3.2.0-6.12-generic 3.2.0-rc6
Uname: Linux 3.2.0-6-generic x86_64
ApportVersion: 1.90-0ubuntu1
Architecture: amd64
Date: Mon Dec 26 13:24:47 2011
DuplicateOf: https://bugs.launchpad.net/bugs/905605
ExecutablePath: /usr/share/software-center/software-center
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20111223)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/software-center /home/username/Downloads/google-chrome-beta_current_amd64.deb
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/software-center', '/home/username/Downloads/google-chrome-beta_current_amd64.deb']
SoftwareCenterLog:
 2011-12-26 13:24:45,849 - softwarecenter.ui.gtk3.em - INFO - EM's: 17 13 20
 2011-12-26 13:24:46,539 - softwarecenter.backend.reviews - WARNING - Could not get usefulness from server, no username in config file
 2011-12-26 13:24:46,647 - softwarecenter.ui.gtk3.utils - INFO - Softwarecenter style provider for ambiance Gtk theme: /usr/share/software-center/ui/gtk3/css/softwarecenter.css
 2011-12-26 13:24:50,764 - softwarecenter.ui.gtk3.app - INFO - software-center-agent finished with status 0
SourcePackage: software-center
Title: software-center crashed with AttributeError in _decode_value(): 'NoneType' object has no attribute 'decode'
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #905605, 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.