Well most cars would have a few wires, usually around 4.,. in your case it sounds like you only have one damadged one as the car will LOCK but when you UNLOCK the short happens.
the problem must be only on the unlock circuit as it doesnt interfere with anything else.,
just give all the wires coming out of the door a good checking and see if you can find any damage.,
Try taking of the door panel and tracing the wires up to the door lock, this way you will know which wires are Central Locking and which are Power Windows, if theres any chops or splice's in the wire, tape it up and try a new fuse to see if the problem is fixed