update-manager crashed with ImportError in /usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeQuirks.py: No module named plugincore.manager

[Matt]

While trying to install updates the update manager crashes and reports an error.

Description: Ubuntu quantal (development branch)
Release: 12.10

apt-cache policy pkgname gives - N: Unable to locate package pkgname

ProblemType: Crash
DistroRelease: Ubuntu 12.10
Package: update-manager 1:0.163
ProcVersionSignature: Ubuntu 3.4.0-5.11-generic 3.4.0
Uname: Linux 3.4.0-5-generic x86_64
NonfreeKernelModules: nvidia wl
ApportVersion: 2.2.3-0ubuntu4
Architecture: amd64
CrashCounter: 1
Date: Thu Jun 21 10:58:23 2012
DuplicateOf: https://bugs.launchpad.net/bugs/1013490
ExecutablePath: /usr/bin/update-manager
GsettingsChanges:

InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120613)
InterpreterPath: /usr/bin/python3.2mu
PackageArchitecture: all
ProcCmdline: /usr/bin/python3.2 /usr/bin/update-manager --dist-upgrade
ProcCwd: /home/matt
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
 TERM=unknown
PythonArgs: ['/usr/bin/update-manager', '--dist-upgrade']
SourcePackage: update-manager
Title: update-manager crashed with ImportError in /usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeQuirks.py: No module named plugincore.manager
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[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 #1013490, 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.