Extension skeleton is givng me grief...

<?php  

if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**
 *  Assign group
 * 
 *   Assign group is an ExpressionEngine extension that allows to assign a newly register member to a predefined group upon registration.
 * 
 * @package        ExpressionEngine
 * @category    Extension
 * @author    Franco Furger <[email protected]>
 * @copyright Copyright (c) 2011 Franco Furger
 * @license   http://creativecommons.org/licenses/MIT/  MIT License
 * @version   0.1
 */


class Assign_group_ext
{
        var $settings        = array();
    
        var $name               = 'Assign group';
        var $version         = '0.1';
        var $description     = 'TBD';
        var $settings_exist  = 'n';
        var $docs_url        = '';

        // -------------------------------
        // Constructor 
        // -------------------------------             

        function __construct($settings = '')
        {
            $this->EE =& get_instance();
            $this->settings = $settings;
        }
    
    
        // --------------------------------
        //  Activate Extension
        // --------------------------------

        function activate_extension()
        {
            
            $data = array(
            'class' => __CLASS__,
            'method' => 'select_group',
            'hook' => 'member_register_validate_members',
            'settings' => '',
            'priority' => 10,
            'version' => $this->version,
            'enabled' => 'y'
            );
            
            $this->EE->db->insert('extensions', $data);
        }
        

        // --------------------------------
        //  Update Extension
        // --------------------------------  

        function update_extension ($current='')
        {

            if ($current == '' OR $current == $this->version) 
            {
            return FALSE;
            }

            if ($current < '1.0')
            {
            $this->EE->db->where('class', __CLASS__);
            $this->EE-db->update('extensions', array('version' => $this->version) );
            }
        }


        // --------------------------------
        //  Disable Extension
        // --------------------------------

        function disable_extension()
        {
            $this->EE->db->where('class', __CLASS__);
            $this->EE->db->delete('extensions');
        }


        //---------------------------------------
        //  Assign group ID to authorized member
        //---------------------------------------
        
        function select_group()
        {
        
        }
}

/* End of file ext.ff_member_assign.php */
/* Location: ./system/expressionengine/third_party/ext.member_assign.php */