I have been all up and down the blogs and forums, and still cannot find an answer, Simply, I think the swf might be too large to load. The swf is made up of three flv's - with about 3 buttons. The flv's are all embedded.
I tested in Flash and DW and everything works very soothly. Once uploaded the link below works fine, it takes a moment to load up, then I press the button and it goes blank. Im assuming the second video is just too large so it takes forever to load. But I hope Im wrong and there is something else I can do.
Try loading them dynamically instead of embedding them. When things are embedded in Flash, as I understand it, they are loaded in the order that the timeline refers to them. This could explain why the first has enough resources to load, and the second one doesn't. I, too, have had a project that would work until I embedded one too many videos.
Loading them dynamically solved my problem and made a much better final product. As an added bonus, you have infinitely more control over the video playback. Refer to the Flash Video Basics tutorials by Lee Brimelow in the Adobe Flash Tutorials section of Creative Cow.