Could you refer to this post or this one
There I tryed to make a compilation of RPC troubles & solutions 
The RPC error is generally related to avast! installation (as Culpeper said), firewall and proxy troubles and some incompatibilities with other antivirus programs (e.g., AVG 6.0). This post relates troubles with more than one RPC service…
As you know, RPC (Remote Procedure Call) is a Windows Service and must be running…