If you are getting the following event id 13508 in your event logs and no 13509 afterward, then this is most likely that the File Replication between domain controllers isn’t working correctly.

File Replication Service Error

Event Type: Warning
Event Source: NtFrs
Event Category: None
Event ID: 13508
Date:
Time:
User: N/A
Computer: DC1
Description:
The File Replication Service is having trouble enabling replication from
DC2 to DC1 for c:\windows\sysvol\domain using the DNS name
dc2 FRS will keep retrying.
Following are some of the reasons you would see this warning.

[1] FRS can not correctly resolve the DNS name dc2 from
this computer.
[2] FRS is not running on dc2.
[3] The topology information in the Active Directory for this replica has
not yet replicated to all the Domain Controllers.
NTFRSUTL.EXE error

ERROR – Cannot bind w/authentication to computer, (null); 000006d9
(1753)
ERROR – Cannot bind w/o authentication to computer, (null); 000006d9
(1753)
ERROR – Cannot RPC to computer, (null); 000006d9 (1753)

1. Check your network settings and make sure everything looks correct

2. Check your firewall and make sure RPC ports are open between domain controllers

3. Check your registry and make sure RPC ports are different between AD and FRS

Good Reference for troubleshooting RPC Endpoint Mapper errors:

http://support.microsoft.com/kb/839880