update-manager crashed with ImportError in __main__: No module named UpdateManager.UpdateManager

[David .]

david@david-K50IJ:~$ lsb_release -rd
Description: Ubuntu quantal (development branch)
Release: 12.10
david@david-K50IJ:~$ apt-cache policy pkgname
N: Impossible de trouver le paquet pkgname

The update program does not launch.
And I can not start a partial upgrade.

ProblemType: Crash
DistroRelease: Ubuntu 12.10
Package: update-manager 1:0.166
ProcVersionSignature: Ubuntu 3.5.0-3.3-generic 3.5.0-rc5
Uname: Linux 3.5.0-3-generic i686
ApportVersion: 2.3-0ubuntu2
Architecture: i386
Date: Tue Jul 10 16:15:27 2012
ExecutablePath: /usr/bin/update-manager
GsettingsChanges:
 b'com.ubuntu.update-manager' b'first-run' b'false'
 b'com.ubuntu.update-manager' b'launch-time' b'1341929448'
 b'com.ubuntu.update-manager' b'show-details' b'true'
 b'com.ubuntu.update-manager' b'window-height' b'526'
 b'com.ubuntu.update-manager' b'window-width' b'640'
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha i386 (20120627)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/update-manager
ProcEnviron:
 LANGUAGE=fr_CH:fr
 PATH=(custom, no user)
 LANG=fr_CH.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/update-manager']
SourcePackage: update-manager
Title: update-manager crashed with ImportError in __main__: No module named UpdateManager.UpdateManager
Traceback:
 Traceback (most recent call last):
   File "/usr/bin/update-manager", line 37, in <module>
     from UpdateManager.UpdateManager import UpdateManager
 ImportError: No module named UpdateManager.UpdateManager
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Launchpad Janitor (janitor)]

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

[Hendrik Schrieber (hennekn)]

Update manager doesn't start from indicator-settings' System menu or from Dash.

[David . (david-suisse1-deactivatedaccount-deactivatedaccount)]

Are not the same problem that the bug in duplicate.

[David . (david-suisse1-deactivatedaccount-deactivatedaccount)]

david@david-K50IJ:~$ update-manager --devel-release
Traceback (most recent call last):
  File "/usr/bin/update-manager", line 37, in <module>
    from UpdateManager.UpdateManager import UpdateManager
ImportError: No module named UpdateManager.UpdateManager

[Launchpad Janitor (janitor)]

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