That's right, thanks a mill for the reply!!!
My problem is that the cable that connects the interior door handle with the door lock.
This happened because the door was frozen and the driver forced the handle. The result is that the cable stretched so much it that it is now too long to work in the other direction and lock the doors.
I took it all apart and have ordered new lock and cable from a Polish website for 40.00Euros. It'll take a week but that's fine.
I'll post the full work with photos when I've finished it.
Last question: Where's the best place on line to get parts, used or new?