Internal Server Error after Customizing Theme

Hello, I was currently customizing my site (using ultimatum theme framework) when I got an "Internal Server Error" message after I refresh the site.

I already tried to search for solution in google which I did:
1. Renaming .htaccess file - doesn't work
2. Increasing PHP Memory Limit - doesn't work
3. Renaming wp-content/plugins folder - doesn't work

Any suggestion on what happened to my site and how to fix it?

The url is http://vision-indo.com/car-accessories

Thanks!