Thickbox won't play flash

Issue Summary

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?