Trouble with MovieClipLoader and Mac Safari

I have written a gallery app that uses a MovieClipLoader object to load jpegs into a grid of thumbnails. The program works flawlessly in Windows Firefox, IE and Safari. On the Mac it works as well in FireFox but in Safari it often freezes up just before the first jpeg is loaded. Only refreshing will allow the program to continue.

You can see the app at

Anyone have any ideas - I’m at wits end!!!