Which way are you turning the crank, Mrgreentie? Clockwise, or counter? Because if you are going counter-clockwise, you're doing it wrong (as they like to say on LOL Cats). The common way to remove a rewind crank from a camera is to put a screwdriver into the fork of the shaft, and turn the crank counter-clockwise.
By binding up the film turning it the wrong direction, you are essentially doing the same thing, jamming the shaft so it won't turn. The screw that holds the crank to the shaft has a right-hand thread, so it should not loosen when turned in the proper direction.
Don't worry, you're not the first one to do this. But I would also check that rewind button papaki mentions, just in case it is contributing to the binding. The film should run somewhat free, with just a little drag as it passes over the pressure plate. And if you let go of the crank before the film leader end gets past the pressure plate, then the crank should spin counter-clockwise on its own as the film tension in the canister is released like a spring unwinding.
Waiting for the light