Doesn't work; not supported.

This plugin does not work for me.

The instructions regarding auto-embed are out of date.

The author does not appear to be supporting this plugin.

I’ve found a working alternative: http://ww.wp.xz.cn/extend/plugins/fitvids-for-wordpress/

Tutorial: http://maketecheasier.com/how-to-embed-responsive-video-to-your-post-in-wordpress/2012/04/30