Standalone Projector won't work on a Mac when output from Mac Flash 8 Pro

I'm outputting a Mac projector file that will work on my mac computer. However, when I upload it to FTP and download it my mac or another mac, it won't work! What's going on? I've tried adding ".app" to my file and it still won't work.

Here's my set up: Flash 8 Pro on Mac Intel with Mac OS 10.4.11