spurious mailman messages

[Joe Mc Cool <joe@benburb.demon.co.uk>]

Oh dear,

during the experiment phases of my mailman installation I subscribed
myself (and my poor long-suffering wife) to the sheep mailing list.
This is described in the user docs.

Now I am getting quite regular mails like the following:

#############################################################
This message was created automatically by mail delivery software.
A message that you sent has not yet been delivered to one or more of its
recipients after more than 1152 hours on the queue on benburb.

The message identifier is:     1EBDwj-0007sZ-2Y
The subject of the message is: subscribe
The date of the message is:    Fri, 02 Sep 2005 16:59:17 +0100

The address to which the message has not yet been delivered is:

  pipe to |/var/lib/mailman/mail/mailman subscribe sheep
    generated by sheep-subscribe@benburb.demon.co.uk
    Delay reason: pipe_transport unset in system_aliases router
#############################################################

I have deleted the sheep list.

How can I stop these please ?

Joe