Is it just me or is the link to the video not working?
I tested it for you and the download does nothing for 20 seconds or so and then it starts.
An alternative is using Youtube Downloader HD and grabbing it from Youtube.
Seems like the downloads are not working for any of the videos.
I tried to download many of the videos from the rest of the Austrian Scholars Conferences, and also the Mises Circle Events. After trying about 15 video links, I stopped testing.