I am getting this error message on a named server...

critical: Unable to get all RR's of zone jolly.ceicmhb/IN with error -303

Server is running NW6SP1... We have an existing server running on NW5.1SP6,
which isn't complaining about it... I can't seem to find anything in the KB,
and I've had a look thru the DNS console, and I can't see anything obvious
that is missing... Is there any way of getting more info out of the server?
I've started it with -dl 2, but it didn't seem to throw anything obvious up.