BitDefender itself is a firewall, BitDefender Internet Security is spam,
adware, etc etc protection.
I have BitDefender Total Security and the moment I install it, Plus! decides its no longer going to load and I get the (till now) never seen before message "Plus -> Software not loaded".
While I'm no novice user, I for the life of me cannot find any other reason that Plus! has stopped working, I use it all the time without problems (other than those that I cause and fix).
If its not BitDefender then I will appoligse, but for now, I'm happy that the problem is with the BitDefender definiation of what Plus! is... That adware thing will likely plague the software till its removed - I frankly don't care one way or another.
Google reports the following links (some non-English).
http://forum.malwarecity.com/lofiversion/index.php/t134.html
So I'll start talking with BitDefender to make sure there is nothing on my end of this software package stopping Plus! from working. And who knows, maybe I will need to say sorry