Fatal Error

Make sure you have at least PHP 5.4 or newer. Looks like your server is outdated.

There is no PHP 5.7. And the 22nd line of EnvatoToolkit.php requires PHP Namespaces, that came into PHP 5.3. So you have PHP 5.2. Or contact your server provider. You can also re-upload the plugin.

Well, re-upload the plugin again. Re-download it. Make sure the file is readable. Check what is on 22 line. It works to 9000 other people, so there is something with your server. You need to contact some PHP developer who would do the work for you ;).