6.1. Failure to exec script. WANTED gid 31, GOT gid -1. (Reconfigure to take -1?)
See also the Mailman FAQ entry at <WANTED gid 0, GOT gid 12 (group mismatch error)>.
The above is an example. If you get this message while accessing one of mailman's CGI pages, it means you must run configure again and go through the install process again, only this time use --with-cgi-gid=-1 (according to the example in the question).
If you got this in a mail context (not CGI), you might try --with-mail-gid=-1.
You should also try running bin/check_perms -f , which may fix this problem.
If you installed from RPMs or some other form of binary package, you either need to get different packages which are configured correctly, or you need to install the correctly configured code from source.
Go to your source for your binary packages to see if they can help you with this problem.
Converted from the Mailman FAQ Wizard
This is one of many Frequently Asked Questions.