Well when I run it through the debugger it memory leaks and hangs which means I'm gonna have to spend some time on it. You could, however, go for the old trick: delete stuff until the problem goes away, then work out which deleted thing fixed it. (Don't forget to backup!) If you could give that a try and let me know what "fixes" it, it could save me a lot of time...
I got it to work by deleting the cursor layer. I dragged the cursor onto the same layer as the main game, and deleted the original cursor layer, and it has worked thereafter.