Mandrake seems to have a bug when it comes to the Mailman web interface --permissions problems occur because of perms problems on log files.
This one stumped for a while until I found the solution below:
Solution: This is caused by msec changing original perms for more restrictive ones. Pending msec updates should solve the issue. In the meantime, just add such a line in your /etc/security/msec/perm.local file: /var/log/mailman/* root.mail 660
Hopefully this will help someone else out as well