This has been happening to me a lot lately. I download a clip or a trailer of something and when I try to play it a message like this pops up. "Couldn't open the file because an unknown error occured. The number of that error is -8971." That's what usually happens with Quicktime player. For Windows Media player this comes up. "The selected file has an extension that is not recognized by Windows Media Player, but the player may still be able to play it. Because the extension is unknown by the player, you should be sure that the file comes from a trustworthy source." This happens for just about all kinds of videos I want to watch that I download. Whatever happened to the good old days were you saved a clip and you could watch it with any media player you wanted.