The BMW keys have to be purchased from the dealership. They have whats called the EWS system, commonly known as the "Drive away protection system". The key has a chip in it which sends a unique code to reciever in the ignition. The codes don't match, the car doesnt start. Thats why their so expensive. I paid around $100 for mine without the light in it. The key will work unless someone has disabled the EWS system which is highly unlikley. A remote cant be purchased anymore, but their are many on ebay.
Now, are you saying when you hit the central locking button none of the locks work? That may be a fault with the central locking system itsef. The ZKE module that controls it is located behind the glovebox. I have never heard of an aftermarket central locking module replacing the OEM one. Thats probably why you have the issue with the wires.