So, on the client machine I get:
----- The following addresses had delivery problems -----
"|/usr/local/bin/procmail /zen1/info/procmail" (unrecoverable error)
(expanded from: <testing-mailbot(_at_)baynestudio(_dot_)com>)
----- Transcript of session follows -----
procmail: Couldn't create "/var/mail/998"
550 "|/usr/local/bin/procmail /zen1/info/procmail" ... Can't create output:
Error 0
The default UID is active when an alias is invoked; typically this is
"nobody". If you wish to have a special UID active when the filtering
occurs of your "mailbot", then you should use the /etc/procmailrcs
feature (see the man page for procmail).
When procmail is invoked with the -m option, and the filter file begins
with the specially configured path (default is "/etc/procmailrcs"),
then procmail sets the UID and GID to that of the ownes uid and gid of
the filter file.
Alan