Door removal problems

[Big Country]

I have just started a project to restore my 67 mustang and have already run into some problems. (This is my first project, so don't laugh at me if i ask for help on an easy problem). My problem is this: the driver's side door won't open, and is therefore causing some problems as we try to take it off the car. We removed the inside panel fro the door so we can see what is going on on the inside, and it appears that as we turn the handle, the cable running to the opening mechanism is being pulled, its just not moving anything on the inside.

Looking at the door we already took off, it appears as if that cable is connected to an assembly which in turn is connected to a pair of gears, which when rotated unlatch the door. When playing with the driver's side door, these gears do not move and seem to be jammed in the shut position. If anybody has any ideas how to get the door to open, i would appreciate it. Alternatively, if there is a way to take the door apart while still on the car to get to the inner workings, that too could be useful.

Thanks in advance for any help.