Could be that the lock cylinder on the drivers door is past its best so you can't disengage the dead lock. Mine is the same. Basically what I did was played around with the key in the lock until finally it opened. I had to do this as all doors were locked

. Once it was open I now never lock the car from the drivers door in case the deadlock activates, just lock and unlock from the passenger door or the boot

.
I have seen this article for fixing the lock cylinder but haven't got round to it yet
http://www.bmwe30.net/cgi-bin/datacgi/d ... Section=01
My ETK gives 2 numbers for the repair kit so take your pick:
51 21 9 061 344
51 21 9 556 313
If you give this a go let me know how it goes
Cheers