Upload de fotos

aparece a seguinte mensagem:

Warning: Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\gcgaming\index.php:1) in C:\xampp\htdocs\gcgaming\includes\common\KT_functions.inc.php on line 464

a linha do documento e:

header("Location: ".$url);

e esse e a function da linha (linha 441 ate a linha 468):

function KT_redir($url) {

	$protocol = "http://";

	$server_name = $_SERVER["HTTP_HOST"];

	if ($server_name != '') {

 $protocol = "http://";

 if (isset($_SERVER['HTTPS']) && ($_SERVER['HTTPS'] == "on")) {

 $protocol = "https://";

 }

 if (preg_match("#^/#", $url)) {

 $url = $protocol.$server_name.$url;

 } else if (!preg_match("#^[a-z]+://#", $url)) {

 $script = KT_getPHP_SELF();

 if (isset($_SERVER['PATH_INFO']) && $_SERVER['PATH_INFO'] != '' && $_SERVER['PATH_INFO'] != $_SERVER['PHP_SELF']) {

 $script = substr($script, 0, strlen($script) - strlen($_SERVER['PATH_INFO']));

 }

 $url = $protocol.$server_name.(preg_replace("#/[^/]*$#", "/", $script)).$url;

 }

 session_write_close();

 $url = str_replace(" ","%20",$url);

 if (KT_is_ajax_request()) {

 header("Kt_location: ".$url);

 echo "Redirecting to: " . $url;

 } else {

 header("Location: ".$url);

 }

	}

	exit;

}

eu uso a developer toolbox do dreamweaver cs4 e uso o xampp.

aguardo respostas, desde ja agradeço.