update-manager crashed with EOFError in /usr/lib/python2.7/dist-packages/UpdateManager/UpdateManager.py: EOF read where object expected

Binary package hint: update-manager

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu.
Description: Ubuntu Natty (development branch)
Release: 11.04

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center.
update-manager:
  Installed: 1:0.147.4
  Candidate: 1:0.147.4
  Version table:
 *** 1:0.147.4 0
        500 http://archive.ubuntu.com/ubuntu/ natty/main amd64 Packages
        100 /var/lib/dpkg/status

3) What you expected to happen.
Expected to see update manager UI.

4) What happened instead.
Update manager crashed before I can see the UI.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: update-manager 1:0.147.4
ProcVersionSignature: Ubuntu 2.6.38-8.41-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Fri Apr 8 23:42:02 2011
ExecutablePath: /usr/bin/update-manager
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python2.7 /usr/bin/update-manager
ProcEnviron:
 LANGUAGE=en_SG:en
 PATH=(custom, user)
 LANG=en_SG.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/update-manager']
SourcePackage: update-manager
Title: update-manager crashed with EOFError in /usr/lib/python2.7/dist-packages/UpdateManager/UpdateManager.py: EOF read where object expected
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare