RPC Server Unavailable Error Message
You run Risetup.exe, or perform an administrative task on the RIS server by using the Active Directory Users and Computers snap-in or any administrative task that requires communication with Active Directory, and an error message appears that indicates that the RPC server is unavailable.
Possible Causes:
There is a problem with the Domain Name System (DNS) server.
Diagnostic Tests:
Run Netdiag to determine the DNS problem, and take appropriate steps to fix the DNS service.