[Mailman-Users] Another easy question

[Jeffery D. Goddard]

Sorry to keep asking the simple stuff but here goes. I've got the 
software set up now and I can create new lists via a web interface. The 
problem is that no one who is subscribing is getting mail back. Once 
again, I've downloaded and compiled mailman. I looked at the 
/etc/aliases file and it looks correct. The /var/log/mail/errors file shows

Apr 16 09:15:01 host-name postfix/sendmail[9574]: fatal: no login name 
found for user ID 502.

The first time I installed mailman (several attempts ago) with the users 
mailman which had a UID of 502. I have sice removed those directories 
and configuration files (as far as I know) but obviously there's still 
something there I missed. I want the UID to be 4 (user mail). Can anyone 
tell me what file I need to edit? I'm using Mandrake 9.0 as my host.

Thanks in advance,

Jeff