Sometimes you just need plain debug on an environment where you do not control the PHP settings. To be able to see what is going wrong in your PHP page just add the following code in the head of your page.

<?php 
error_reporting(E_ALL);
ini_set('display_errors', '1');
?>

Dont’ forget to remove it once it is all corrected. A good practice is to have the same PHP version on development, test and production machines.