update notifier crashes unexpected at startup

[caziel]

Binary package hint: update-notifier

here ist the console-output:

ALSA lib confmisc.c:1105:(snd_func_refer) Unable to find definition 'defaults.pcm.dmix_format'
ALSA lib conf.c:3500:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:3957:(snd_config_expand) Args evaluate error: No such file or directory
ALSA lib pcm.c:2145:(snd_pcm_open_noupdate) Unknown PCM dmix:AudioPCI
checking for valid crashreport now

ProblemType: Crash
Date: Tue Feb 27 08:45:57 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/caziel
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
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 digitalkaoz 2.6.20-8-generic #2 SMP Tue Feb 13 05:18:42 UTC 2007 i686 GNU/Linux