I had the same problem and found I had to adjust the shift linkage. If I recall, there is a set bolt on the linkage near the transmission. You loosen it, move the linkage a bit in the correct direction and retighten it. It took me a few times to get it right.
Took a look at the linkage everything is all hooked up fine..some sort of electrical issue? The seat belt interlock is disabled. Is there something in the steering colum?