Portable Prezi won't open

I have downloaded a portable Prezi, but cannot get it to open. This is strange because I did this successfully with two Prezis I created last year.

I notice that the portable prezis I downloaded last year appear in my folder with a Flash player icon. The new one I have just downloaded has a Prezi icon. I click on it, and the opening process starts, but freezes up about three-quarters of the way round.

This is my Prezi:

http://prezi.com/zopoflud0wq3/gd-dxpe...

Any help much appreciated.