Need pointed in the right direction intranet DNS's

[baltoinfo]

I've been banging my head with this one.
My setup.

Lab1 1 DNS Server bind9.3.1/linux witha zone xxx.com on a
192.168.99.0/24 network
Lab2 1 DNS Server bind9.3.1/linux witha zone xxx.com on a
192.168.1.0/24 network

Corp. DNS on 192.168.77.0/24 network which has the complete company DNS
names.

Both Lab1 and Lab2 DNS work fine with what ip/names I've added, however
I can't get the two Labs to query nor send a query to the main corp
dns.

I hope that makes since.
Thanks in advance.