Can't resolve domain name

I apologize if this is a duplicate posting

I have a DNS server (BIND 9.2.2) setup on my home LAN connected to the
internet via broadband. I'm running Linux, 2.6 kernel and I forward
queries to my ISP. Everything seems to work OK except that I cannot
resolve my domain. If I "dig mydomain.com" I get this back:

<<>> DiG 9.2.2 <<>> mydomain.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 58781
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;thethurmans.com. IN A

;; AUTHORITY SECTION:
mydomain.com. 86400 IN SOA myserver.mydomain.com.
lorenzo.mydomain.com. 200205241 28800 7200 2419200 86400

;; Query time: 18 msec
;; SERVER: 192.168.2.16#53(192.168.2.16)
;; WHEN: Tue Nov 9 17:15:09 2004
;; MSG SIZE rcvd: 83

But if I query for a particular CNAME, I get an answer:

; <<>> DiG 9.2.2 <<>> www.mydomain.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40130
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;www.mydomain.com. IN A

;; ANSWER SECTION:
www.mydomain.com. 259200 IN CNAME myserver.mydomain.com.
myserver.mydomain.com. 259200 IN A 66.149.68.238

;; AUTHORITY SECTION:
mydomain.com 259200 IN NS ns.mydomain.com.

;; Query time: 31 msec
;; SERVER: 192.168.2.16#53(192.168.2.16)
;; WHEN: Tue Nov 9 17:18:30 2004
;; MSG SIZE rcvd: 90

This happens from both inside my LAN and also from the outside, at
work. nslookup also behaves the same. It might be that I don't
understand dig, but I'm not sure how to proceed. I've read various DNS
docs and I own an OReilly book on DNS administration, but I at a loss to
understand what's happening.
Any ideas?
TIA