exact mailman error from post fix

The email I got back from postfix starts on the next line:
	From: 	  [email protected]
	Subject: 	Undelivered Mail Returned to Sender
	Date: 	August 16, 2006 6:32:38 AM MST
	To: 	  [email protected]

This is the Postfix program at host blindtechs.net.

I'm sorry to have to inform you that your message could not be
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to <postmaster>

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

			The Postfix program

<[email protected]>: Command died with status 2:
     "/opt/local/libexec/mailman/mail/mailman request azcb". Command  
output:
     Group mismatch error.  Mailman expected the mail wrapper script  
to be
     executed as group "mailman", but the system's mail server  
executed the mail
     script as group "nobody".  Try tweaking the mail server to run  
the script
     as group "mailman", or re-run configure,  providing the command  
line option
     `--with-mail-gid=nobody'.
Reporting-MTA: dns; blindtechs.net
X-Postfix-Queue-ID: 2B1E4FE2B6
X-Postfix-Sender: rfc822; [email protected]
Arrival-Date: Wed, 16 Aug 2006 06:32:38 -0700 (MST)

Final-Recipient: rfc822; [email protected]
Action: failed
Status: 5.0.0
Diagnostic-Code: X-Postfix; Command died with status 2:
     "/opt/local/libexec/mailman/mail/mailman request azcb". Command  
output:
     Group mismatch error.  Mailman expected the mail wrapper script  
to be
     executed as group "mailman", but the system's mail server  
executed the mail
     script as group "nobody".  Try tweaking the mail server to run  
the script
     as group "mailman", or re-run configure,  providing the command  
line option
     `--with-mail-gid=nobody'.

From: Gabriel Vega <[email protected]>
Date: August 16, 2006 6:32:28 AM MST
To: [email protected]
Subject: help








Gabriel Vega
The BlindTechs Network
email: [email protected]
website: http://blindtechs.net
  Phoenix (602) 476-2307 ext: 2863
Los Angeles (562) 261-5277 ext: 2863
Toll Free (866) 714-4244 ext: 2863