[Exim] UID error with mailman

2001-08-15 13:52:35 15WzDv-00087F-00 <= jajoa@??? H=spencer.wm.net
(relay2.wm.net) [194.18.224.226] P=esmtp S=2058
id=E500C07A3D64D31182F00008C7DB99280456DEBA@WMSI000168
2001-08-15 13:52:35 15WzDv-00087F-00 Neither the system_aliases director nor
the address_pipe transport set a uid for local delivery of
|/home/mailman/mail/wrapper mailcmd test

ANy hint to where to set the uid? And which should it be? I am guessing the
Exim uid?