2001 BMW X5 Unable to open/unlock back doors at all

[Comanche]

Problem: I have a 2001 BMW X5 that I am unable to open/unlock the back doors by any means.
One morning I went to get in my vehicle and tried to unlock/open the X5 using the key in the door unlock cylinder. I do not have a REMOTE KEY nor have I used one for the last 4 years. I turned the key the correct way to unlock the doors and the key acted as if it turned freely but stopped at its normal position, the doors would not unlock nor did the alarm sound. After trying to unlock the X5 using my key, my wife’s and the valet keys, I contacted a service advisor at my local BMW dealership. He did not know of any way to get the X5 unlocked. He visited with one of the mechanics and even looked at a similar 2001 BMW X5 and still had no suggestions other then to call BMW NA, a locksmith or tow it to the dealership. I called BMW NA and they were unable to offer any advice other the to inform me that my warranty had expired. After calling several locksmiths I located a locksmith who was familiar with BMW’s. He was not able to get the drivers side door unlocked, however he was able to open the passenger door and set off the alarm. I immediately put my key in ignition and started the vehicle and the alarm went off. I pushed the central lock button and none of the doors or the tailgate would unlock. I tried to unlock the remaining doors with the key using the drivers door unlock cylinder, however the doors still would not unlock. I was able to open the drivers side door using the interior door handle, but neither one of the rear doors would unlock using this method. I tried the procedure of holding down the central locking button and using the interior door handle at the same time however the rear doors still would not unlock. The drivers side door lock cylinder still turns freely to it normal positions to the left and right while using a key however it will not lock or unlock anything. I can open the tailgate using the button in the center consol while the drivers or passengers door is open, but only then . I had to use the emergency release in the right rear compartment to get to the gas cap. The automatic locking feature at 5 miles per hour does not work. Has anyone else experienced anything similar to this problem? I am a little mechanical, so if anyone has any solutions that I can try I would welcome your ideas. Thanks Comanche