mailman/sendmail question

[Michael Sullivan]

I installed mailman (again) and I set up the mailman mailing list and it
says it will send the list owner a notification that the list was
created.  I never receive the notification.  I go into the mailman logs
and in the smtp-failures log it says that an email from mailman-bounce
was denied with a User Unknown error.  The
/usr/share/mailman-2.1.4/INSTALL.REDHAT says that this error can happen
if the mailman list is not properly set up in /etc/aliases, but it was
properly set up in /etc/aliases because I never deleted it from the
previous installation.  I've run newaliases and tried setting up the
mailman list again (after removing it, of course)  I've tried restarting
the mailman service and creating other lists and I cannot get past this
error.  Pleas help!