This video is unavailable
Unfortunately, this video is not available in Germany because it may contain music for which GEMA has not granted the respective music rights.
That's strange, because the YT post is from the copyright holder himself (PSY) so there shouldn't be any rights issues. I don't understand your GEMA organization.
Just search YOUTUBE for "gangnam style". I'm sure you'll find at least one version which you can play.
Or, try this, the official video:
http://www.youtube.com/watch?v=9bZkp7q19f0(It makes me happy whenever I play GANGNAM STYLE!

... in fact, so happy, I'm tempted to make my own parody version.

)
FYI, the original link (which you can't play) is a live concert version where 30,000 people are joining in with all the words.
When I first started watching it, I couldn't quite understand why half the audience was wearing blue plastic waterproof ponchos ... but the reason soon became apparent!

Apparently, he also gave a free copy of his album to all 30,000 attendees!