Door lock broken.

I am having problems with {the door lock} on the driver's side.
Passat, manufactured in 1997
Can rotate in all directions without resistance... without success. However, the central locking system functions perfectly from the passenger door.

Is it just a minor issue, or is the problem more serious?
Maybe someone can give me a tip on where I should start looking for the problem, before I scrap the door panel!
Thank you!