[Exim] missing lookup type

I'm getting the following in my logs from a new router I've put in to
use couiers 'deliverquota'. I can't understand why I'm getting a
'missing lookup type' when I have put one in!

==> /var/log/exim/exim_panic.log <==
2004-02-13 17:49:12 1AqW1k-0000PK-PK == test@???
R=testing_director T=testing_pipe defer (0): Expansion of "${lookup"
from command "/usr/sbin/deliverquota -c
/home/mail/${domain}/${local_part} ${lookup mysql {SELECT quota FROM
SAS2.mail WHERE domain LIKE '${quote_mysql:$domain}' AND localpart LIKE
'${quote_mysql:$local_part}' AND type='alias'}{$value}}" in testing_pipe
transport failed: missing lookup type

Perhaps I'm missing the obvious, but this is really puzzling me.

If anyone can help, I would be very greatful..

Kind Regards,

Ian P. Christian