It appears this script is causing the issue:
<script type="text/javascript" src="dmxAppConnect/dmxAppConnect.js"></script>
When I remove that line the page functions properly. I'm not sure if you need it.
It appears that script is removing the form button from the submitted values, so the "Button Press" events in the server behaviors won't work.
You can either remove that line, or update your server validation and email server behaviors to use the "any form post" trigger instead.