error

[eluser]Unknown[/eluser]
I would like to do this tutorial:
tutorial,but when I written in the browser,[url=http://localhost/CodeIgniter/index.php/books/main]browser[/url
The error:

Code:

load->model('books/books_model'); } function main(){ $this->load->view('books_main'); } function input(){ $this->load->view('books_input'); } } ?>

A PHP Error was encountered

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\CodeIgniter\system\application\controllers\Books.php:18)

Filename: codeigniter/Common.php

Line Number: 360

Why?

Monique