What FP's did you have Mele? To date, I have not had any. Used to run Avast at my job as well and never had any. So either a lot of us have lucked out, or something in your setup was throwing up a fp (which happens). Of recent times, the av that I have had the most FP's with is WSA. Thankfully it has done nothing dentrimental to any of my systems or the ones that I have to support.
FYI I even run Avast on my Exchange 2010 server at work. No issues. -- This space for rent.