The Postfix program

<lenhador-news@saturno.fazendosistemas.com.br> (expanded from
   <lenhador-news@lenhador.com>): Command died with status 2:
   "/usr/local/mailman/mail/mailman post lenhador-news". Command output: Group
   mismatch error.  Mailman expected the mail wrapper script to be executed as
   group "nogroup", but the system's mail server executed the mail script as
   group "mailman".  Try tweaking the mail server to run the script as group
   "nogroup", or re-run configure,  providing the command line option
   `--with-mail-gid=mailman'.