Hi Cebby,
I just spoke with Markus about this. He thinks that one possibility could be that RocketThemes is loading MooTools too late (it's loading AFTER jQuery). That causes the global namespace to be broken. There is an extension that can control this:
www.elovaris.at/en/downloads/jquery-includer
Can you try installing it and see what happens?
Also, when I did a test submission of your form, I got a "PHP Mailer failed" error. You would need to check your Joomla global configuration settings for that.
Please let me know if this corrects things for you.
Thanks!
Terry