This is not an RTMPE video. It is a simple HTTP stream. You can download it with Replay Media Catcher (RMC) after cleaning the cache of your browser. You can also use the Video History Tool of RMC to save the video from the cache of your browser.

You can also download this video without installing any software using web-sites like http://download-youtube-videos.org/

If you want to use rtmpdump to download the video, then use the great advice by hyc mentioned in the previous post.