Mailman CGI error!!!

The Mailman CGI wrapper encountered a fatal error. This entry is being stored in your syslog:

Group mismatch error.  Mailman expected the CGI
wrapper script to be executed as group "www-data", but
the system's web server executed the CGI script as
group "fsa".  Try tweaking the web server to run the
script as group "www-data", or re-run configure, 
providing the command line option `--with-cgi-gid=fsa'.