Just to let you know (I don't know if you know any better or not) the files aren't ACTUALLY emailed to avast (they were previously I think). They actually get added to a file, and when you do your next update (either manually or automatically) they are uploaded to avast for an analysis.
I can't remember if it gives you a dialogue box or not, depending on if it worked or not, but it should be working.
If it's not, it's usually because of a remnant A/V product. If you haven't had a competing A/V product installed on the system recently, it's probably working fine. If not, let us know what A/V product you had, and we'll try to provide you a way of removing it completely, so avast works correctly.