This may take a few seconds to load.
If it doesn't load AT ALL it will probably ask you whether you want to install some software.
It's safe, and free, and it's probably worth having anyway. Install it, then come back and play the video again.

Once it loads (with a big blue 'a' followed by an li-uk page), there will be a small right pointing triangle under the picture of the site. Click it. Enjoy....