do-release-upgrade crashed with ImportError in /usr/lib/ubuntu-release-upgrader/check-new-release: No module named DistUpgrade.DistUpgradeVersion

[gogo]

do-release-upgrade crashed with ImportError in /usr/lib/ubuntu-release-upgrader/check-new-release: No module named DistUpgrade.DistUpgradeVersion

ProblemType: Crash
DistroRelease: Ubuntu 12.10
Package: ubuntu-release-upgrader-core 1:0.170
ProcVersionSignature: Ubuntu 3.5.0-4.4-generic 3.5.0-rc6
Uname: Linux 3.5.0-4-generic x86_64
ApportVersion: 2.3-0ubuntu4
Architecture: amd64
Date: Wed Jul 11 12:21:56 2012
ExecutablePath: /usr/bin/do-release-upgrade
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120629)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/lib/ubuntu-release-upgrader/check-new-release -q
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
PythonArgs: ['/usr/lib/ubuntu-release-upgrader/check-new-release', '-q']
SourcePackage: ubuntu-release-upgrader
Title: do-release-upgrade crashed with ImportError in /usr/lib/ubuntu-release-upgrader/check-new-release: No module named DistUpgrade.DistUpgradeVersion
Traceback:
 Traceback (most recent call last):
   File "/usr/lib/ubuntu-release-upgrader/check-new-release", line 8, in <module>
     from DistUpgrade.DistUpgradeVersion import VERSION
 ImportError: No module named DistUpgrade.DistUpgradeVersion
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[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 #1023055, 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.