[apport] apt-check crashed with ImportError in <module>()

Binary package hint: update-notifier

update-notifier crashed after an update.
I updated from the notifier, not from the terminal.

ProblemType: Crash
Architecture: i386
Date: Mon Feb 26 17:32:24 2007
DistroRelease: Ubuntu 7.04
ExecutablePath: /usr/lib/update-notifier/apt-check
InterpreterPath: /usr/bin/python2.5
Package: update-notifier 0.56
ProcCmdline: python /usr/lib/update-notifier/apt-check
ProcCwd: /home/lili
PythonArgs: ['/usr/lib/update-notifier/apt-check']
SourcePackage: update-notifier
Traceback:
 Traceback (most recent call last):
   File "/usr/lib/update-notifier/apt-check", line 6, in <module>
     import apt_pkg
 ImportError: No module named apt_pkg
Uname: Linux LILY 2.6.20-8-386 #2 Tue Feb 13 05:15:43 UTC 2007 i686 GNU/Linux