Domain Mapping 500 Internal Server Error

http://knowledgekollege.celestialwebdesigns.com/

This site was there. I turned on domain mapping without having the sunrise.php in place. I didn't set up the plugin at all. I accidentally forgot.Then I turned on a domain in the domain mapping and everything on the site crashed.

How do I fix this? I deactivated the domain mapping tool but it hasn't fixed anything. I honestly don't know what to fix.