php - CodeIgniter cannot load database library manually or autoload; Call to Member function get() on a non object

I'm unable to load the database library correctly manually in my model or in autoload.php

The line $query = $this->db->get('videos'); produces a Call to Member function get() on a non object error indicating the database library is not loaded.

I try loading the database library using the two lines commented out in the constructor for the model below but both return errors. If I uncomment $this->load->database I get a Call to member function database() on a non object error,

If I uncomment $this->load->library('database') I get a Call to member function library() on a non object error

<?php 
class Videos_model extends CI_Model {
  public function __construct()
    {
        parent::__construct();
        //$this->load->database();
        //$this->load->library('database');
    }

    public function get_videos() 
    {
           $query = $this->db->get('videos');
    }

}
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The same line $this->load->database(); in the controller does not produce an error but the get() function error.

class Videos extends CI_Controller {

    public function __construct() {
            parent::__construct();
            $this->load->helper(array('url'));
            $this->load->database();
             //$this->load->library('database');
            $this->load->model('videos_model');
            $this->videos_model->get_videos();           
    }
}
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I also have set autoload in the config file,

$autoload['libraries'] = array('database');
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in my CI Log file database driver is indicated to be initialized DEBUG - 2013-05-09 15:31:17 --> Database Driver Class Initialized

Here is my database config as well,

$active_group = 'default';
$active_record = TRUE;

$db['default']['hostname'] = 'localhost';
$db['default']['username'] = 'dbusername';
$db['default']['password'] = 'dbpassword';
$db['default']['database'] = 'dbname';
$db['default']['dbdriver'] = 'mysql';
$db['default']['dbprefix'] = '';
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = TRUE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = '';
$db['default']['char_set'] = 'utf8';
$db['default']['dbcollat'] = 'utf8_general_ci';
$db['default']['swap_pre'] = '';
$db['default']['autoinit'] = TRUE;
$db['default']['stricton'] = FALSE;
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I'm using CI 2.1.3 in eclipse with aptana studio 3 plugin and phpMyAdmin 3.5.8.1 and Apache Server 2.2

Update: I've confirmed that accessing the database works from the controller but not the model.