There was an update which could have fixed this problems: http://forum.avast.com/index.php?topic=138753.0
Check out the latest version 9.0.2007 only just released.

You can try a manual program update from the avastUI as version 9.0.2007 is now available, see http://forum.avast.com/index.php?topic=138753.0, for more information.

Thank you. That seems to have resolved the issue.