Problems with BIND: SERVFAIL

[tab4by]

Hi,

i'm running a bind / nameserver on BIND9. On this server a couple of .be
domains are already running and active.

The problems started using .com-domains. I use the same configuration for
all of them but when I do a dig / nslookup on the .com, I got a SERVFAIL.
When I'm setting the server to mine, it just works fine.

extraction of /etc/named.conf
zone "some-domain.com" {
        type master;
        file "/var/lib/named/some-domain.com.hosts";
                allow-transfer {
                        123.123.123.123;
                };
        };


the .hosts file itself:
$ttl 3h
some-domain.com. IN      SOA	www.gabriel-hosting.be.	info.gabriel-hosting.be. (
                        2004070302
                        3h
                        1h
                        1w
                        1h )
some-domain.com. 	IN     	NS      www.gabriel-hosting.be. 
some-domain.com. 	IN	NS      external-dns.com. 
some-domain.com.     	IN	A       62.213.193.147

I hope anyone can help me,
thanx in advance

Tim Brouckaert