I was really baffled by this too. My stick was completely free and the gear was stuck in reverse. I could move my stick around but I couldn't move it into any gear positions, it was the strangest thing. I did all sorts of things to try and "free up" my transmission, but manually pushing it back after removing the reverse light indicator was the only thing that worked.

Thinking back on it now, I remember that it happened when I killed my engine while I was moving backwards in reverse. I had to kill my engine because my clutch bracket is busted and the only effective way of stopping the vehicle was to turn if off ....so that I wouldn't run into the parked cars behind me. Then when I tried to put it into first gear after killing the engine I realized that my stick was not going into any gears... so I tried to wrestle it into gear for awhile thinking that it wouldn't go into gear because my clutch wasn't getting full stroke because the broken clutch bracket was flexing off the firewall. I then started the engine thinking that the transmission was in neutral and it immediately started moving backwards in reverse much to my surprise and horror. I immediately killed the engine.... and then I struggled with it for hours. Finally I wedged my broken clutch bracket to where I could push my clutch in enough to where I was not longer engaging my reverse gear... and then my friends pushed me into my garage. I then discovered the above posted forum (5 weeks later) and after reading it I was able to free my transmission from reverse.