Can't connect to Domain Controller in Windows 2000 server

Here is my network setup: A wireless Access Point that acts as DHCP
and assigns all my laptops dynamic IPs. It assigns the server a static
ip address (192.168.2.50).

Initially all my computers had a workgroup called something. Now the
server has domain xyz.com.

From one of my laptops I can ping the server and vice versa. However,
when I try to change this laptop's workgroup to a domain (xyz.com) I
get the following error:

"A domain controller for the domain xyz.com could not be contacted.

Note: This information is intended for a network administrator. If
you are not your network's administrator, notify the administrator
that you received this information, which has been recorded in the
file C:\WINDOWS\debug\dcdiag.txt.

The following error occurred when DNS was queried for the service
location (SRV) resource record used to locate a domain controller for
domain xyz.com:

The error was: "DNS name does not exist."
(error code 0x0000232B RCODE_NAME_ERROR)

The query was for the SRV record for _ldap._tcp.dc._msdcs.xyz.com

Common causes of this error include the following:

- The DNS SRV record is not registered in DNS.

- One or more of the following zones do not include delegation to its
child zone:

xyz.com
com
.. (the root zone)

For information about correcting this problem, click Help."

What can I do to fix this?