Preloader works on PC but not Mac versions of Firefox and IE

Go here:
http://xezton.com

Throw the piece of trash that says “Music News” away. A window should pop up with a little black preloader and after it loads a little media player will appear.

At least that’s what SHOULD happen.

I developed the site in Flash MX Professional on MacOSX. When I look at the site through Firefox or IE on a PC, the preloader works PERFECTLY.

When I look at the site on a mac (either in IE or FireFox) the preloader doesn’t even show up.

Why is this? And is there any way to fix it? I can post some of my code if an obvious answer isn’t found.

Thanks.

–Xezton