What is the full version number from about avast, 4.8.xxx ?
I doubt that message is anything to do with it, commonly this means that you have enabled the avast Outlook/Exchange provider and it is waiting for you to start MS Outlook (not express). So if you have that enabled and you don't use MS Outlook then disable it.
How long have you had avast 4.8 and was it previously working (e.g. not reported by WSC) ?
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.
I would also suggest that there is little worth in trying to do much chasing this down, I would recommend that you download avast 5.0 and install that.