Prog mailer exited with EX_TEMPF

I want to have mail go to different queues based on email address. Following
the advice on the wiki I did the following:
set up an alias: rt-dev: "|/etc/smrsh/rt-mailgate --queue general --action
correspond --url http://my.company.com"
ran newaliases
I set up a symlink: cd /etc/smrsh; ln -s /bin/rt-mailgate rt-mailgate

When I send a mail to rt-dev no ticket is created and I see the following
when I run mailq
Deferred: prog mailer (/usr/sbin/smrsh) exited with EX_TEMPF)
"|/etc/smrsh/rt-mailgate --" etc…

Can anyone offer some advice on how to resolve this?

Regards

Cameron