I work a responsive child theme on my localhost before I make it live. My child theme technique is to copy the style.css to my child theme folder, and edit to suit my needs. I was having trouble with this plugin; so I decided to work the problem live so I could get help with a live demo.
And wham! The plugin worked on the live site. http://gregory-george.com/
I am wondering (out loud) if there is a php extension that is running on the live host that is not on in my localhost?
Also, For those in need of more documentation... http://themeid.com/responsive-opt-out-plugin/