On a windows 2003 server I had troubles to log on via RDP. I got the message every time that the “RPC server is unavailable”. I got this error also when I tried to log on to the Console of the server via RDP.
Event Type: Error Event Source: Winlogon Event Category: None Event ID: 1219 Date: 13-12-2011 Time: 13:06:45 User: N/A Computer: Server-Name Description: Logon rejected for domain\administrator. Unable to obtain Terminal Server User Configuration. Error: The RPC server is unavailable. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. Data: 0000: 000006ba
To solve this issue you need to connect to the server > services > TCP/IP NetBIOS Helper this services you need to restart after the restart you are able to log on again to the system with RDP