Can you try to repair your installation?
Go to Control Panel > Add/Remove programs > avast! antivirus > Remove
Then choose Repair function in the popup window (Repair).
Do you have any other antivirus installed in your computer?
Did you have in the past? Which one?
RPC error is generally related to other antivirus present or, at least, firewall blocking. Do you use a firewall? Which one?
Have run the repair function on my installation but without success after reboot.
Repair loaded some files but didn’t return a comment if repair was successful or failed.
Started repair function second times and rebooted. This time avast was activated. (Icon in tray turns around ;D) )
A curious thing is that when I click on “about Avast” in system tray under VPS-File there is an entry: “No information available: VPS-File was destroyed”
I have currently not installed any other antivirus software and had never installed another on my current system.
I use a hardware firewall/router zyxel