Unable to join domain, receive domain controller not found error

I recently had some problems with my internet upgrade and had to change the DNS entries on my DNS servers ( which are 2 seperate machines running win server 2003).
since then, i have not been able to add any xp pro machine to the domain, i receive an error. I have one server as the domain controller and 2 other machines serving as DNS servers. Is there something that i need to update on my domain controller when i changed the DNS entries on the DNS servers? Anyone else experience something similiar?