Beginner's Guide to Adobe Flash/Publishing/Projectors
A projector in terms of Flash is an standalone executable file format that Flash can save a movie into in order to allow someone to view the movie without having a flash player or a Shockwave plugin previously installed.
The standalone Projector for PC comes with the normal .exe extension, while the Mac Projector published on PC comes with .hqx extension. HQX is not an executable file, it is a compressed file format (kind of like Mac's Zip file) which packs together the two file forks Mac files have: the Data fork and the Resource fork. The .hqx file will not open on a PC if you double-click on it (because it has to be decoded), and it will not work if you burn it like that on CD with PC.