[Resolvido] Aviso na linha Lang

Bom, vou direto ao ponto, alguém saberia me dizer como resolver esse problema ou aviso seila

Warning: Cannot modify header information - headers already sent by (output started at /srv/disk8/2953546/www/dominio.com/security/funcao.php:1) in /srv/disk8/2953546/www/dominio.com/security/config.php on line 7

Arquivo.: config.php

if(isset($_GET['lang'])):
$lang = $_GET['lang'];

$_SESSION['lang'] = $lang;
setcookie('lang', $lang, time() + (3600 * 24 * 30));

elseif(isset($_SESSION['lang'])): $lang = $_SESSION['lang'];
elseif(isset($_COOKIE['lang'])): $lang = $_COOKIE['lang'];
else: $lang = "en";
endif;

switch ($lang) {

default:

	include "dice/language/lang_eng.php";
break;

case "pt":

	include "dice/language/lang_ptbr.php";
break;

case "en":

	include "dice/language/lang_eng.php";
break;

}