[Mailman-Users] post to mailman from mailman-owner

[ThirdRock Support]

I have an old Mailman installation (2.1.14) using postfix virtual domains.
There was a problem with permissions, and so a lot of messages were shunted.
I fixed permissions, and mailing lists are working, but list moderator
requests are not being sent.
My 'post' logs a are filled with messages saying:

Feb 03 22:39:34 2012 (30455) post to mailman from mailman-owner at mydomain.com,
size=1694, message-id=<mailman.4011.1328072998.27420.mailman at mydomain.com>,
1 failures

This message repeats every few seconds.
My mailman managed alias file does have what I think are the correct
entries for the mailman list:

# STANZA START: mailman
# CREATED: Thu Jun 23 22:10:23 2011
mailman:             "|/mailman/mail/mailman post mailman"
mailman-admin:       "|/mailman/mail/mailman admin mailman"
mailman-bounces:     "|/mailman/mail/mailman bounces mailman"
mailman-confirm:     "|/mailman/mail/mailman confirm mailman"
mailman-join:        "|/mailman/mail/mailman join mailman"
mailman-leave:       "|/mailman/mail/mailman leave mailman"
mailman-owner:       "|/mailman/mail/mailman owner mailman"
mailman-request:     "|/mailman/mail/mailman request mailman"
mailman-subscribe:   "|/mailman/mail/mailman subscribe mailman"
mailman-unsubscribe: "|/mailman/mail/mailman unsubscribe mailman"
# STANZA END: mailman

Can anyone point me in the correct direction to fix these problems?

Thanks
Paul