Slide In won't display on mobile site

I've done a slide-in demo for a client here http://bluegekko.co.uk/competition-demo/
But I can't get it to display on the mobile site I'm building for him (this page http://dev7.bluegekko.co.uk/pop-up-demo/)

It's a mobile site using the JumpMobi theme.

Any ideas?

Many thanks

Ben