New W2K computers won’t join W2K Domain

We recently upgraded our Windows NT4 server to Windows 2000 server. The installation seemed to go very smoothly, until I tried to add a new W2K machine to the domain. All computers that belong to the domain before the upgrade were still part of the domain, but when trying to add a new W2k machine, I get the error:
“The following error occurred attempting to join the domain “flaftmss”:
The network path was not found.”

This is the correct domain name; I have DHCP enabled.

My server also shows this error in the event log:
“Dynamic registration or deregistration of one or more DNS records failed becasue no DNS servers are available.” This is also a new error since the upgrade.