Ok, so I’ve seen this before. It’s rare, but it happens. Your server is generating an internal server error from the theme’s shortcode generator. Specifically, it’s this file:
It’s impossible to know for sure without having access to your server’s error log, but most likely it’s a mod_security issue. This is an extension of Apache that some hosts have setup more restrictive than others. I have a feeling this is what it is. Just contact your webhost, tell them that file is generating an Internal Server error always on your server, and they’ll be able to see why and most likely fix it.