Heat will not help. You cannot get the loctite or whatever has it seized up (friction?) hot enough to make a difference because the action acts as a heat sink (is that the term?) and robs you of the heat it would take to break it free. Put a short allen wrench "socket" into the head of the screw and hit it with a hammer. This is not difficult, nor is it an uncommon "problem". Trust me. The proper way to loosen the screw is to do what I told you to do. :)

Oh, yes. What Bowhntr said was what I was trying to say.
Sorry.