What browser and OS are you on? If you can hear audio but no video, it's probably a browser/ Flash plugin issue. Might try reinstalling flash or your browser, or try it in another browser.
This computer runs on Windows (not sure which version) and internet explorer. I guess it oculd be a plugin issue but I didn't get any messages.
Here's something weird. I tried the Last Airbender again, then Clash of The Titans, then Jaws 3 and I couldn't see any of them, but then after I refreshed Jaws 3 it started showing the video. So I tried refreshing Last Airbender, but that one still didn't work. Furthermore, I just tried Jaws 3 again and even after I refreshed it's still black this time. Am I the only person with this problem? I should probably be posting in technical support.