The first time I jammed the camera, I was fooling around with it (it was new to me). I fixed it with a screwdriver.
The second time, my wife started to remove the lens, then handed it to me to finish. This is a bad idea. I accidentally fired the shutter with my hand. We had to disengage the gearing to remove the lens - not fun, but we were able to fix it in the middle of the desert with a jewelers screwdriver.
So, don't be stupid like me and all will be fine!