You don't have permission to access /CodeIgniter/application/controllers

[eluser]Unknown[/eluser]
i'm new to codeigniter, trying to follow instruction on how to install it from the user manual but whenever i try a sample of a program in a controller i like this
<?php

class Site extends CI_Controller(){
function index(){
echo'hello';
}
}
?>


i got this error: Forbidden! You don't have permission to access /CodeIgniter/application/controllers

i'm using codeigniter v 2.1.2

please help!!