DC replication problem Help, please

I am having difficulties to replicate a new DC controller with the other DC in the Domain.

I experienced some connecivity problems while i was configuring a new DC in to our domain. Server name does not appeared on the GC.

When i run DCPROMO to demote this server (so i can promote later) i get an error.

are there any sites for DC server replication issues.

Thanks in advance