Slide In Plugin not working for Mailchimp Sign Up

I've installed the Slide In plugin to use as a Mailchimp signup form. The slide in works as it should however when I tested it by entering my email address and then hitting submit, nothing happens. The slider doe not go away and no confirmation. Any ideas? It's for http://fruitcakemovie.com. I've got the slider in draft mode for now until I can get it fixed so let me know when you want me to enable it for testing. Thank you!