Yep, Avast had a number of issues with this particular update. This was fixed though (hence your "delete" comment, I'm sure ;)). Had me miffed for a while too :)
Hate to admit this, but I lost a little sleep over this. The word was that this Avast problem might brick the machine if rebooted. I left the computer on overnight through a terrible wind storm, just the kind that tends to knock out power. This morning: power, sunshine, and a revised Avast virus definition file.