Fatal Memory Error in version 3.1.6+

You are right! The problem is something to with loading of library. I commented off each line that loads a library and the error went away.

So how should I load a library? This is how I have been loading...

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Roots extends CI_Controller {

public function __construct()
{
parent::__construct();
$this->load->library('base');
$this->load->library('utilities');
$this->load->library('session');
$this->load->library('auth');
}

public function start()
{
}
}