Domain Controllers Security Breakdown

I have 2 Server 2003 domain controllers at different locations connected via a VPN. The VPN was down for a while. I decided to force the domain controllers to synchronize. However, after doing that, I am not able to log into one of the domain controllers. I get the following error:

“The system cannot log you on due to the following error: Access is denied.”

I think the security permissions and SIDs go messed up when I forced a synchronization. Does anyone know how to fix this problem? I can still access the computer’s file shares, but I can not access services (DHCP, DNS, etc.) Help!