If you ever got this message:
Failure to exec script. WANTED gid 67, GOT gid 0
Here is mailmans security explained:
http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq06.016.htp
this means: the file /etc/mailman/mailman.mail-gid should contain the gid of the calling MTA. And this is not the mailman-gid! Edit the file and replace the 67 with 0 and it should work!
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