When you right-click on My Computer / Properties / Network Identification / Properties and try to join a Windows NT domain, you receive:
The following error occurred validating the name "domain name".                              The specified domain either does not exist or could not be contacted.
If you NET VIEW, you receive:
System error 53 has occurred.                              The network path was not found.
When you try to ping by name, it fails, but pinging by IP address is successful.

If your only protocol is TCP/IP and you disabled NetBIOS over TCP/IP, that is probably your problem.

This can also be caused by some 3rd party DNS servers, that do not support SRV records.

To enable NetBIOS over TCP/IP:

1. Start / Settings / Network and Dial-up Connections.

2. Right-click Local Area Connection and press Properties.

3. Select Internet Protocol (TCP/IP) and press Properties / Adsvanced / Wins.

4. Click Enable NetBIOS over TCP/IP.

5. Press OK until you are out. You can ignore the 'empty primary WINS address' message.

If you don't want to enable NetBIOS over TCP/IP, you could install NetBEUI on the clients and the server.