'embedding youtube' problem..

I am setting up a new diary post, due to go out on Monday afternoon at 3pm. partly I've delayed it because I can't get the 'embed video' block to work.
Here is the draft:
http://screencast.com/t/skElzrgp

I put the code into the block window and press the 'embed 'button; then either it just goes round in circles, or disappears up into the 'readmore separator' block;
http://screencast.com/t/R96nIM8a5FXy
I have updated Easyblog to the latest version in case that was the problem.

Can you help please?
The video itself is ok:
https://youtu.be/7LlWYKjDzqE


thanks, Robin