[Mailman-Users] mailman-owner problem

[b udhi19]

Dear all,
i've installed mailman 2.1.3 on My BSD machine, and run postfix
as my MTA. i've create a list and then i try to sent a mail
to list that i've created, but it seem not work
then i check the log on my mailman directory and i found this on my
smtp-failures log :

Dec 06 15:59:38 2003 (499) delivery to mailman-owner at jalak.bi.itb.ac.id failed with code 450: 
<mailman-owner at jalak.bi.itb.ac.id>: User unknown in local recipient table

i've add aliases on my /etc/aliases
but still not work...
i've read FAQ, and i found the same problem as mine but it seem still not answer for that,
anyone ever have this problem and have solved this problem?

regard, 
Budhi