Cryptic Error Message

I've been getting this cryptic error messages for several days on my Debian Sid:

warning: Non-ASCII character '\x8b' in file /usr/lib/python2.3/codecs.py on line 2, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details
'import site' failed; use -v for traceback
Traceback (most recent call last):
File "/usr/bin/apt-listchanges", line 34, in ?
import DebianControlParser
ImportError: No module named DebianControlParser

It was started after I got a rather big disk f*ckup, which need standalone mode fsck. Many broken files (fortunately, only application ones, not my data), but I think all or most of them has been repaired. python and apt-listchanges has been reinstalled, nothing changed. Haven't had chance to do more debugging ...