why does my SketchyPhysics 3x freeze when I press play?

forgot to post picture whooops

Whenever I press start, my sketchup freezes, and turns off. I attached a picture of what happens when I press play. I REALLY NEED HELP!
Thanks in Advance.

Hello, this is my first post.

I used SketchyPhysics 2 for about 2 months, and I finally got the hang of it.

But whenever I try to use default for shape, it just still recognizes as a Box, so I can't make gears. How do I fix this problem, and where can I get SketchyPhysics 3 RC1 ? (maybe it's RC3 or whatever)

Thanks in Advance!