Google has recently changed some code to block RealPlayer and I think your problem may not be related to Adobe.
Bob, GeoMG is right.
RealPlayer ISN'T Adobe, and Google HAS updated YouTube code. RealPlayer is a terrible program though. It's invasive, conflictive, and just plain unreliable as a player, streaming app, or downloader.
If you use Firefox, get the Ant Video downloader extension. You can download videos while you watch them, and it DOESN'T conflict with other plugins like Flash Player. There are downloaders available for Chrome, and Opera as well. IE unfortunately, leaves you at the hands of RealPlayer, which as you see now, isn't working.