Postfix +mailman = troubles

[termleech]

I'm trying to set up mailman and postfix on my gentoo box. I've followed the instructions on the gentoo.org site as well and the instructions I found on the forums. Currently, I have alias_maps= hash:/usr/local/mailman/data/aliases in /etc/postfix/main.cf. I also have set up a list for mailman and have run the genaliases. I have restarted both postfix and mailman. However when I am trying to send email to the list under mailman, I'm getting the following error in mail.info

Mar 28 20:25:44 carnation postfix/smtpd[32018]: 2625E3B2C9: reject: RCPT from mail1.WPI.EDU[130.215.36.102]: 450 <chairmen@tkezm.org>: User unknown in local recipient table; from=<chaines@WPI.EDU> to=<chairmen@tkezm.org> proto=ESMTP helo=<mail1.WPI.EDU>

Any help would be much appreciated.
_________________
-----------------------------
Chuck Haines
GDC Webmaster
http://gdc.wpi.edu
WPILA Labmanager
http://www.wpila.org
-----------------------------