If you get a HTTP 500 Internal Server Error or blank page while trying to load a PHP page, this is due to a PHP fatal error. As a security messure, we do not send PHP errors to the browser. They are logged on the server php error log.
In order to view the PHP errors, you can:
1) Enable the display of errors in the browser (Only recommended for development or debugging purposes, not finished sites)
Create a .htaccess file with the following line in it: php_flag display_errors 1