I think that I don't have a problem after all.
I just went to Avast user interface/Account. It shows Subscription Status: Valid. (see image #1)
However the Avast tray icon has a red X on it's face. The white flag icon (Action Center) also has a red flag on it. Opening Action Center (see image #2) says to "Turn on Avast Antivirus. Nothing happens when I click on box "turn on".
Well you clearly do have a problem as the avasu installation doesn't show you are registered when my.avast.com does. Since you are using the UI it is important to resolve the problem and get avast running also.
Try a repair of avast:
XP - Add Remove programs, select 'avast! Anti-Virus,' click the Change/Remove button and select Repair, click next and follow.
OR
Vista, win7 or later - Control Panel, Programs & Features, uninstall a program, select 'avast! Anti-Virus,' click the Uninstall/Change and select Repair, click next and follow.
You should reboot after the repair.
This has in the past resolved this out of sync issue on data displayed (or not displayed) and the data behind the scenes.