[Mailman-Users] Can't create new mail list

[HSU NORML]

Running latest version of mailman with the mailman/joomla bridge on a joomla
server.
at /mailman/admin/ i click on the link to create a new mail list and i
receive a page:
Internal Server Error

The server encountered an internal error or misconfiguration and was unable
to complete your request.

Please contact the server administrator, webmaster at hsunorml.org and inform
them of the time the error occurred, and anything you might have done that
may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 404 Not Found error was encountered while trying to use an
ErrorDocument to handle the request.
How do I get beyond this?