I never had the problem fixed on my X-5 and am living with it. I did learn that it is possibly a general service module that controls the windows and door locks. My wife's '02 325 has the exact same problem with the locks. A new module can set you back as much as $800 or possible more. I would have the BMW dealer diagnosis the problem and get a cost estimate.

You may find a used module on ebay, but it would have to match the one you currently have in your X-5. Some of the modules are different on the same year models.

Let me know how you take care of your problem, if you find a fix. I hope this helped.