When configuring Windows Server 2012 Remote Access as a DirectAccess server with Mark Litscher, I ran into one of those vague RPC error messages that we all know and love. After running through the DirectAccess setup wizard and clicking Apply, the "Applying Remote Access Setup Wizard Settings" window would open up and start running through the configuration process, but when it got to "Retrieving domain information." it hung for a bit, then said "The remote procedure call failed." After that it would rollback the configuration and we were stuck at the console with an unsaved, non-applied configuration.
After doing some digging around, I discovered there were two old domain controllers that had been removed from Active Directory long ago, but they were still showing up in the list of DC's. Using "nltest /dclist:" showed then with no associated sites, so it was pretty obvious that something wasn't quite right there.
Using Active Directory Users and Computers (ADUC), we were able to find these computer accounts which were already disabled, and then deleted them. This cleaned up the dclist and the DirectAccess wizard completed successfully.
Hope that helps!