Having trouble joining domain on win2k

I have a small network setup at home with a 2000 advanced server and 2 2000 pro wkstn. When I try to add the domain (with administrative privileges) I get an error: unable to locate domain “MYDOMAIN”:
network path not found. However, I am able to see my server and browse through the network neighborhood. I am also able to map a drive. I also have internet connection (cable modem)which is shared from the server and is working on all the machines just fine.
Thanks for your help…