Problem with extjs and codeigniter

Code:
&lt;?php

    class Login extends Controller

    {

        public function __construct()

        {

            parent::Controller();

            $this->load->model('drugdb','use');

            $this->sets        = parse_ini_file("./extends/global.ini");

            $this->local    = parse_ini_file($this->sets['rela'].$this->sets['ini'].__CLASS__.$this->sets['type'],true);

        }

        

        public function index()

        {

            $this->load->library('validation');

            $this->load->helper('form');

            $this->load->helper('cookie');

            $data['title']        = $this->local[__FUNCTION__]['title'];

            $data['error']        = '';

            $data['rootPath']    = $this->local[__CLASS__]['rootPath'];

            $username    = $this->input->post('username');

            $passwd        = $this->input->post('passwd');

            $rules['username']    = 'callback_username_check';

            $this->validation->set_rules($rules);

            if ($this->validation->run()    == false)

            {

                $this->load->view($this->sets['viewPath'].'/'.$this->local[__CLASS__]['viewFloder'].'/'.$this->local[__FUNCTION__]['viewName'],$data);

            }

            else

            {

                set_cookie('username',$username,0);

                set_cookie('logged',true,0);

                redirect('drugindex');

            }

        }

        

        public function username_check($str)

        {

            $passwd        = $this->input->post('passwd');

            $count        = $this->use->get_count('admin',array('username'=>$str,'passwd'=>md5($passwd)));

            if ($count >0)

                return true;

            else

            {

                $this->validation->set_message('username_check','<span class="highlight">login error</span>');

                return false;

            }

        }

    }

?&gt;