I know you are suppose to use f4 to switch to rearview but when hit it on the keyboard it brings up a command for my computer it has no game function please help

If memory serves, if you don't have anything in the rear view to tractor in - then it will give this error. I remember being very frustrated during this sequence until I figure out that without having something to tractor in - then the beam didn't work...

Best thing to do is cut the engines almost to nill and then line up the object close to directly behind you then give it a shot.