[Exim] Unknown user to specifed localuser

Hi,

I'm using exim for three months now and have choosen
it to be my standard MTA. I am a sysadmin by a small ISP
with over 50 domains and a school.

I'm new to this list...

My problem is that I want to send all email to unknown
users to an exsisting user.

Exim 3.03 did this ok with the following lines at the
end of the DIRECTORS CONFIGURATION:

userunknown:
driver = smartuser
transport = local_delivery
new_address = uu@???

But when I upgraded to Exim 3.11 I get this error in the paniclog:

1999-12-21 14:08:01 120Nh1-000761-00 Neither the userunknown director nor the lo
cal_delivery transport set a uid for local delivery of blablabla@???

What am I doing wrong here?

Regards,

Onno