I managed to install the plugin and it seems to be working as the Featured Video Box is where it should be. However when I copy and paste the code from Youtube, nothing happens. The dimensions that I need for my site are 480 by 420, and in the embed code they are 480 by 270 - perhaps that is the problem. I tried to change the code once I'd pasted it but no luck.
Maybe updating to the latest version of WordPress would make a difference.