David, since your last post was less than an hour ago, I presume you're still having this problem?
It must vary considerably from one user's system to another ... I did get the same thing with repeated scanning of FirewallUI.exe, as I'd noted in another thread somewhere (the main "Final released" one, maybe?), but adding the PCTools folder to my File Shield exclusions (not the global exclusions, under Settings) cleared that up nicely yesterday and -- so far, at least -- avast hasn't found another file "worthy" of the same attention. The tooltray icon remains at rest unless something's actually happening.
Between that, and the extremely useful tip of resetting ShowSetupOutro in the INI to get rid of that phoenix-like "finish installing" thing, I think I've finally got my avast back into normal running condition, plus of course the new features. Speaking of which, since the new auto-sandbox so far has too small a database to be of any use, and insists on terminating nearly anything I start, I've simply disabled that until it's more functional, like the WebRep will hopefully become.