I'm stuck in the same situation. I'm running XP and using the 4.5 version of Avast. All of a sudden, in the last week I've been unable to get any updates. I've manually downloaded the last two updates so that I could scan & make sure I don't have some new bug. The #80 error message is general, without a specific cause, simply stating that the program was unable to get the update from avast. I killed my XP firewall and rebooted to make sure it wasn't causing the problem, even though Avast is checked off on my permitted access list. I scanned my whole hard drive for viruses but found none. This is the first problem I've had with Avast and I've been using their products for over a year and have been VERY happy with them. I tell everyone I can about this great software and have many converts. Any insight would be greatly appreciated - I don't want to continue running around the web without my firewall or missing my updates!