After upgrading Plesk mailman won't work anymore. You find messgaes like this one in your mail log :
Failure_to_exec_script._WANTED_gid_67,_GOT_gid_12./Failed_to_start_/usr/lib/mailman/mail/mailman./did_0+0+1/
Check /etc/mailman/mailman.mail.gid
Login as user mailman an execute /path_to_mailman/bin/check_perms
After this every thing will be fine (tested on SuSE 9.3 an Plesk 7.5 Reloaded
Good luck
Harry
Failure_to_exec_script._WANTED_gid_67,_GOT_gid_12./Failed_to_start_/usr/lib/mailman/mail/mailman./did_0+0+1/
Check /etc/mailman/mailman.mail.gid
Login as user mailman an execute /path_to_mailman/bin/check_perms
After this every thing will be fine (tested on SuSE 9.3 an Plesk 7.5 Reloaded
Good luck
Harry