It's not an avast error itself (
http://forum.avast.com/index.php?topic=4818.msg65672#msg65672).
It seems a RPC (Windows) error.
Why don't you search the board for
error 1753 and see if any thread helps?
Which is your Windows? 98, Me, XP?
Do you use any other antivirus in your computer?
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). You must be connected to the internet while repairing.
If this does not help, can you uninstall / boot / install / boot again?