Any ideas why I am unable to download video from YouTube anymore with RealPlayer Downloader?

Ever since yesterday afternoon I have been attempting to download videos from YouTube using the RealPlayer Downloader to show in the classes that I teach and the downloader says "Unable to download" for every video. I uninstalled and reinstalled the program and it still does it. Any ideas what might be... show more Ever since yesterday afternoon I have been attempting to download videos from YouTube using the RealPlayer Downloader to show in the classes that I teach and the downloader says "Unable to download" for every video. I uninstalled and reinstalled the program and it still does it. Any ideas what might be wrong with the downloader? Or can you recommend another free program that I can use to download video from YouTube?