zipfile problems

[Austin Luminais]

I have an archive of several hundred zip files, and I'm trying to
automate unzipping them with the zipfile module (Python 2.2,
Activestate).  Most of them work, but 58 of them don't.  Most that
don't work get this error:

BadZipfile: File is not a zip file, or ends with a comment

And a few get:

BadZipfile: Unsupported compression method 6 for file (filename)

WinZip and Powerdesk have no problem extracting these files.
Would this be considered a bug in zipfile or zlib, or would they
instead be considered corrupt files that WinZip happens to handle?

A few of the files are available here:
http://www.chromosome57.com/python/badfiles/

alonerbm.zip gives the unsupported compression method error, and the
others give the "not a zip file" message.