PHP codeigniter

Question

Hi! I used php and codeigniter version 3.1.7. But show below error I couidn,t solve it. Can you help me?

 

A PHP Error was encountered

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at Z:\home\dit.tj\www\application\controllers\pages.php:1)

Filename: core/Common.php

Line Number: 570

Backtrace:

File: Z:\home\dit.tj\www\index.php

Line: 315

Function: require_once

404 Page Not Found

The page you requested was not found.