Thickbox won't play flash

I've been trying to hunt down the answer on other sites, but it looks like thickbox won't play flash. I'm trying to load movies in a "splashcast player and find that the sound will play but the movie isn't viewable. Strangely, the links to the movie controllers work (though they are invisible, but if I find them I can click with mouse) and when I click the play button the sound is audible.. I'm assuming this is some sort of css issue where the thickbox css is hiding the movie. Any ideas?