Launched software-center after today's update and it popped up this message. Although the app did not crashed in reality as I could install k3b :). I am experiencing this with my Oneric installation. It reports a crash but apps do work even after the so-called crash...
ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: software-center 4.1.23.3
ProcVersionSignature: Ubuntu 3.0.0-11.18-generic 3.0.4
Uname: Linux 3.0.0-11-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 1.23-0ubuntu1
Architecture: amd64
Date: Mon Sep 19 19:22:52 2011
ExecutablePath: /usr/share/software-center/software-center
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110901)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/software-center
PythonArgs: ['/usr/bin/software-center']
SourcePackage: software-center
Title: software-center crashed with IndexError in __getitem__(): could not find tree path '1441'
UpgradeStatus: Upgraded to oneiric on 2011-09-16 (2 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare
Status changed to 'Confirmed' because the bug affects multiple users.