[Exim] mysql Lookup problem?

hide mysql_servers = localhost/courier/userhere/passwordhere

mysql_user:
   driver = smartuser
   condition = ${lookup mysql{select id from passwd \
                where id='{$local_part@$domain}'} \
        {$value}{fail}
   transport = vdom_delivery

and thsi gives:

2001-08-22 16:55:50 15ZZQ6-0007U6-00 <= j2@???
H=h71n1fls21o907.telia.com (animal.mupp.net) [212.181.140.71] U=root P=esmtp
S=679 id=Pine.LNX.4.10.10108221655470.32162-100000@???
2001-08-22 16:55:50 15ZZQ6-0007U6-00 == muuh@???
D=mysql_user defer (-1): condition check lookup defer

uhm, why?