DNS and File Replication

I need some help to figure out what is wrong with my DNS. I am setting up a addtiont domain controller (win 2000) as a backup domain controller in a 2k3 domain. I am having problems with the replication. get event 5781 warning, 13508 NTfrs about not being able to replicate.
I think this is linked to sometine in the DNS config. It is not set to do dymanic updates is there something I need to do manually?
If I do a nslookup it says can’t find server name
non existant domain. Domain server unknown?

I don’t know to much about DNS so any insight would be greatly appreciated.
Thanks
Jerrett