update-manager crashes after starting upgrade to quantal

[blackiwid]

$ update-manager -d
authenticate 'quantal.tar.gz' against 'quantal.tar.gz.gpg'
extracting 'quantal.tar.gz'
can't load DistUpgradeViewGtk3 (Failed to open file '/tmp/update-manager-eFrYgB/DistUpgrade.ui': No such file or directory)

$ lsb_release -rd
Description: Ubuntu 12.04 LTS
Release: 12.04

$ apt-cache policy update-manager
update-manager:
  Installiert: 1:0.156.14.5
  Kandidat: 1:0.156.14.5

What I expected to happen:
     upgrade to Quantal Quetzal would start

What did happen instead:
     update-manager crashed with error message

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.5
ProcVersionSignature: Ubuntu 3.2.0-26.41-generic 3.2.19
Uname: Linux 3.2.0-26-generic x86_64
ApportVersion: 2.0.1-0ubuntu8
Architecture: amd64
Date: Wed Jul 11 17:55:22 2012
ExecutablePath: /usr/bin/update-manager
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1342022102
 com.ubuntu.update-manager window-height 694
 com.ubuntu.update-manager window-width 675
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120301)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcEnviron:
 SHELL=/bin/bash
 TERM=xterm
 PATH=(custom, user)
 LANG=de_DE.UTF-8
SourcePackage: update-manager
UpgradeStatus: Upgraded to precise on 2012-07-11 (0 days ago)
VarLogDistupgradeMainlog:
 2012-07-11 17:55:51,550 INFO Using config files '['./DistUpgrade.cfg']'
 2012-07-11 17:55:51,551 INFO uname information: 'Linux neptun 3.2.0-26-generic #41-Ubuntu SMP Thu Jun 14 17:49:24 UTC 2012 x86_64'
 2012-07-11 17:55:51,551 INFO apt version: '0.8.16~exp12ubuntu10.2'
 2012-07-11 17:55:51,552 INFO release-upgrader version '0.170' started
 2012-07-11 17:55:51,846 WARNING can't import view 'DistUpgradeViewGtk3' (Failed to open file '/tmp/update-manager-eFrYgB/DistUpgrade.ui': No such file or directory)

[Launchpad Janitor (janitor)]

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