Why is my swf animation not moving?

I have an animation of a physical experiement with a .swf-file. This animation has no end, because it starts every time new when the experiement is complete. I open it with Microsoft Media Player, but I can’t insert it in Prezi. If i try it, there is only a picture of the experiement in Prezi, not the whole  animation. What can I do? 
Thanks for every answer!

Thank you for help!
Moritz