@word_press_user: all video iframes shows fine in firefox.
I have latest version of firefox, it is ver.:24.0 for the moment.
Try to update your firefox or check out the page with all extensions disabled.
Some content blocking extensions (like AdBlock and so on) could block your iframe videos.
kind of strange: I am using version 24.0 too, I deactivated all (=three) plugins and I still can’t see the videos. It looks it is because of my configuration. It is making me happy, that you and hopefully the other visitors can see it… 😉