How do I Fix this alert:"Assertion Failure"

Hello,

I'm working in this game right now:

http://therealgeekgirl.com/pruebamuseo/

And even it is working when you play it uploaded on the server (like the link before) when I'm working on it and launch it on local host I get this failure alert:

I look at every colision mask and physics and it seem to be all ok... not sure what to do now to fix it, some help please?

regards.

No ideas?? thanks for your time

Usually best if a simple .capx is provided as it enables others to test out the issue. Diagnosing from a screeenshot is not really the best.