Adding W2k machine to NT4 Domain

[Dave]

When trying to add my Win2000 workstation machine to our NT4 domain I keep getting the Error message "The following error occured validating the name"Domain name". The specified domain either does not exist or could not be contacted." Also I can Ping any other machines on the subnet apart from DC's, I get time outs on these, on IP address and computer name.

Cheers in Advance

Dave