If you are still having problems with those locks (more than likely your problem is the latches) then look
here.
I encountered two problems with my rear doors:
Driver's side: This latch was rusted to the point that the part that releases the "claws" would not move. When I finally got the door open it was a matter of a removing the latch and giving it a good cleaning and lube job.
Passenger's side: This latch assembly has a spring dissolve into a rusty dust cloud before I bought the car. Once the door was opened, the latch assembly was removed and repaired as indicated in the link. The missing spring is what prevents the door from unlocking.
On a side note, my drivers side rear door is no longer opening. More than likely the spring on this side has gone bye byes as well. I just havent had time to get in there since it had happened.