I currently use an unregistered (yet) pro-version of avast 4.6 on Windows XP.
A friend of mine just sent me a file that avast detected as infected. The file, according to this friend, is nothing more than a Camtasia avi movie packed with a viewer in a .exe file.
This friend scanned his file with Norton, nothing wrong.
I can send it to you: what e-mail address to you want me to use for this?
(You will probably receive the file tomorrow: I have to ask my friend to send it back to me because I deleted it when I saw that it was possibly infected…)