RDP : RPC Error you say?

If on the older version of terminal services you get this error on login, and you can connect to the registry and remote services, however RDP fail with this:

 "The system cannot log you on due to the following error: The RPC server is unavailable"

Navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server

Create the following key:

Name: IgnoreRegUserConfigErrors
Value : 1