I am at 5.0.418 and when I click on "Maintenance’ and “update program”, I get “cannot connect to server”. I did purchase a 3-PC license a few weeks ago, installed everything correctly (or so I think I did)…
I don’t see anyone else posting “cannot connect to server” problems. \
Unfortunately the XP firewall has zero outbound protection, so it shouldn’t interfere with the avast updates.
Is the program showing that the License is a) valid, not invalid or b) the license has expired ?
If either of these are correct then avast wouldn’t let you update.
So when you bought the license was it for avast Pro version 5.0 ?
If so was that entered in the UI, Maintenance, Registration section ?
I ran into this message when I attempted to update a 418 version also. I found the simplest solution was to download the Avast version currently on avast.com, and run it. It will offer to upgrade your version, and I found that once I did this, I had no further troubles with updating either the virus sigs or the programme itself.