Mercedes: Door wont lock from the outside(190E 1990), few days, doors

Question
I just bought this car a few days ago and I can no longer lock the "doors" from the driver side.  I have to go to the passenger side to lock the door.  I can unlock the door from the drivers side just not lock it.

Any suggestions would help.  How much do you think a repair like this might cost?

Sincerely,

Patrick

Answer
Answer:
Best advice:
Take this to your local dealer.

If you must DIY; please read these threads first.

Inner Door Panel Removal DIY Links
http://www.mercedesshop.com/shopforum/showthread.php?t=150747

Door LOCK issues, link thread.
http://www.mercedesshop.com/shopforum/showthread.php?p=1214456