Maggie, you need to put the link in the little narrow box, not in the main text - but make sure the link is correct, there's a spelling mistake in your OP Media URL: http://youtu.be/1O6p84lYw7s Description:
youtu.be is what you get if you click on the share button under the video but do not use that - you can either copy the address from the address bar in your browser or if you are using Firefox and the Tab Max Plus add-on (which is great for other tab controls anyway) a 'Copy Tab URL' is included in the tab menu.