Two things to get the inline video viewer to
work:
1. Use the Insert Link button (the globe w/ the chain link icon)
2. Use a clean link to the YouTube video. You had all that "?feature=player_detailpage&" junk in your url which probably screwed it up. A clean link will always end in "watch?v=xxxxxxxxxxx". You can get that by searching for your video on YouTube and clicking straight to it, rather than viewing it from some other location (like a link on another website; or from the Recommended sidebar on YouTube).
Edit: it looks like your video is set to not allow embedded viewing, so people will have to click on the link if they want to watch it.