@camokid11 said:

hi Joe, i think i can explain this.

http://sketchupusers.vacau.com/index.php?topic=115.msg1267#new

this topic basicly asked the same question, and the conclusion was Sketchup 8 uses a newer version of ruby which isnt liked by Sketchyphysics (all version i believe).

Sketchup 7 works fine on windows 7, but Sketchup 8 i havnt tried.

My advice, if you can, switch back to sketchup 7 to use sketchyphysics.

I've skp pro 8 on a windows 7 and man do I have a lot of bug when i do try 2 run a sketchy physics models