Confirmed on Firefox 2 with XP. Card 1 just says "mission expired" in the box on the right. Card 2 plays the mission info still.
Do you have the "no script" extension? (If not, you should. It's awesome and necessary, esp. on Windows.)
jpdyson has great questions. Answer those and we'll go from there.
semi-related note: sure wish the briefings could be watched on an iPhone, but you can't drag-and-drop. Maybe the cards could be clickable on the iPhone's browser as an alternative?!
Whistle while you work. Patience is key.