Could someone please tell me how to forward-lock normal 3GP files, so that you cant bluetooth the file to anyone.
You can't, and I don't think Nokia will either (because you're supposed to be able to send .3gp files in MMS messages, etc.).
What's your objective? Why are you trying to prevent that in the first place? If we knew that, perhaps there'd be some other solution to whatever the problem is that you're trying to solve.
The company i work for sells mobile video downloads to phones that play 3gp files, and I need to make sure that when users download the clips that they cant forward them on via bluetooth. Is there a piece of software that does this?