1. Log into the Domain controller either in console or via RDP
2. Download DcDiag.exe from microsoft if you do not have the Windows 2000 support tools installed. You can find it at http://www.microsoft.com/downloads/details.aspx?familyid=23870A87-8422-408C-9375-2D9AAF939FA3displaylang=enYou can download it and extract it to anywhere you like.

3. Open a command window (Start menu -> Run -> Type 'cmd' with out quotes and hit enter/click ok), now change directory to where the executable is located.
4.

Type 'ipconfig /flushdns', then 'ipconfig /registerdns' (with out the quotes) to flush out the DNS resolver cache and register the DNS source records, respectively.Some people like to clear the ARP cache as well, you can do this by typing 'arp -d *' at the command prompt with out quotes. This part is optional.
5. At the prompt type in dcdiag /fixRead through the output. You will most likely have the following text somewhere in your output:Server GUID DNS name could not be resovled to an ipaddress.
Althought GUID could not be resolved, the server name resolved to the ip address x.x.x.x and was pingable
6. Still at the command prompt, type 'dcdiag /fix', then 'net stop netlogon' and 'net start netlogon' (again with out the quotes) to finalize the changes.Run dcdiag one more time to make sure the domain controller's DNS is working. You should no longer get the error mentioned in step 5. Some other NIC related errors may show up, but you can dismiss those for the most part it wont affect your installation (you couldnt get this far if there were serious NIC problems)
7. You should now be able to add member computers to your new domain and add domain controllers.