Problem with quering BIND on localhost

[Johan Schröder]

Hello,

I have a -probably simple- question. I'm runnung BIND 9 on a Ubuntu 
server and I've already set up different zone files. When I try to query 
BIND on the local machine, I get this error:

 > nslookup www.domain.com localhost
Server:         localhost
Address:        127.0.0.1#53

** server can't find www.domain.com: SERVFAIL

I do not understand why I get this error, because BIND is already 
running and also a ACL is set up.

Regards, Johnny