i didn't really have trouble with em, i did aquire a couple of scrapes tho!!
did you try the lock mech plugged in the car but not fixed in? you need to move the workings about a bit. they get stuck/loose poition or whatever and need to be fiddled with.
also you could try turning the levers for the key part of the lock mech, i noticed sometimes it seems to be worn and not quite turning far enough.