Could you please contact ‘Minacross’ by IM or email. See here.
He is from Egypt and, maybe, could help you in the configuration of your arabic Windows.
If it helps, you could take a look at You probably have at these forums on which were discussed RPC errors and solutions:
http://www.avast.com/forum/index.php?board=2;action=display;threadid=1864;start=msg12339#msg12339
(or http://www.avast.com/forum/index.php?board=2;action=display;threadid=1730;start=msg11102#msg11102 or http://www.avast.com/forum/index.php?board=2;action=display;threadid=1317;start=msg10900#msg10900).
Anyway, RPC (Remote Procedure Call) is a Windows Service and must be running because avast! depends on it. The majority of the times, the trouble is on the user system configuration and state and not on avast! installation.