Location C:\Program Files\Alwil Software\Avast4\ashUInt.dll (avast User Interface Common Module) same size and date modified.
It may well be a one off and there are better ways to get to avast.com, browser bookmark, but it is strange.
Try a repair of avast. Add Remove programs, select 'avast! Anti-Virus,' click the Change/Remove button and scroll down to Repair, click next and follow. You need to be on-line to do this.