What had caused this error on my side was the following line
include_once dirname(__FILE__) . './Config.php';
I managed to realize it was the culprit when i added the lines:
//error_reporting(E_ALL | E_DEPRECATED | E_STRICT);
//ini_set('display_errors', 1);
to all my php files.
To solve the path issue
i canged the offending line to:
include_once dirname(__FILE__) . '/Config.php';