我收到以下错误：
致命错误：在第 32 行的 C:\wamp\www\jobsite\application\controllers\main.php 中的非对象上调用成员函数 set_userdata()
我无法识别错误，您能帮忙吗？
错误消息快照链接：
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Main extends CI_Controller {
public function index()
{
$this->login();
}
public function login(){
$this->load->view('login');
}
public function members(){
$this->load->view('members');
}
public function login_validation(){
$this->load->library('form_validation');
$this->form_validation->set_rules('email','Email', 'required|trim|xss_clear|callback_validation_credentials' );
$this->form_validation->set_rules('password','Password', 'required|md5 ');
if ($this->form_validation->run()) {
$data = array (
'email' => $this->input->post('email'),
'is_logged_in' => 1
);
$this->session->set_userdata($data); /* Line 32 */
redirect('main/members');
} else {$this->load->view('login') ;
}
}
public function validation_credentials(){
$this->load->model('model_users');
if($this->model_users->can_log_in()) {
return true;
} else {
$this->form_validation->set_message('validate_credentials', 'Incorrect UserName / Password');
return false;
}
}
}