Phew! I dodged a bullet!
I just got to evaluating the camera this morning, a two days after I unloaded the camera in frustration, and I found that after opening the back of the camera, the frame counter wheel reset itself. With a full rotation to cock the shutter, the timer freed itself, thereby freeing the shutter. The timer seems to work fine now, and I taped the (M - X) lever down to prevent this from happening again.
I guess this is it! Thanks snederhiser + cramej!