Warning: Cannot modify header information

On cart when try to proceed I get this error:
Warning: Cannot modify header information - headers already sent by (output started at... /httpdocs/siicom_cart.php:5) in .../httpdocs/siicom_cart.php on line 105

This is code in cart.php
...
<?php
//WA eCart Include
require_once("WA_eCart/eCart1_PHP.php");
?>
<?php
$eCart1->GetContent();
?>
<?php
// WA eCart Update
if (isset($_POST["eCart1_Update_100"]) || isset($_POST["eCart1_Update_100_x"])) {
$eCart1->UpdateCart();
$Redirect_redirStr="";
if ($Redirect_redirStr != "") {
$eCart1->redirStr = $Redirect_redirStr;
}
$eCart1->cartAction = "Update";
}
?>
<?php
// WA eCart Continue Shopping
if (isset($_POST["eCart1_Continue_100"]) || isset($_POST["eCart1_Continue_100_x"])) {
$Redirect_redirStr="";
if (true && isset($_SESSION['WAEC_ContinueRedirect'])) {
$Redirect_redirStr=siteToPageRel($_SESSION['WAEC_ContinueRedirect']);
}
if ($Redirect_redirStr != "") {
$eCart1->redirStr = $Redirect_redirStr;
}
$eCart1->cartAction = "Continue";
}
?>
<?php
// WA eCart Clear Cart
if (isset($_POST["eCart1_Clear_100"]) || isset($_POST["eCart1_Clear_100_x"])) {
$eCart1->ClearCart();
$Redirect_redirStr="";
if ($Redirect_redirStr != "") {
$eCart1->redirStr = $Redirect_redirStr;
}
$eCart1->cartAction = "ClearCart";
}
?>
<?php
//WA eCart Redirect Check Out
if (isset($_POST["eCart1_Checkout"]) || isset($_POST["eCart1_Checkout_x"])) {
$Redirect_redirStr="noGatewayCheckout.php";
if ($Redirect_redirStr != "") {
if (isset($_SERVER['QUERY_STRING']) && $_SERVER['QUERY_STRING'] != "") {
if (strpos($Redirect_redirStr, "?") < 0) {
$Redirect_redirStr .= "?".$_SERVER['QUERY_STRING'];
}
else {
$Redirect_redirStr .= "&".$_SERVER['QUERY_STRING'];
}
}

$eCart1->redirStr = $Redirect_redirStr;
}
$eCart1->cartAction = "Checkout";
}
?>
<?php
// WA eCart Redirect
if ($eCart1->redirStr != "") {
header("Location: ".$eCart1->redirStr); **** line 105*****
}
?>


Any idea to resolve?

Hi

First thing to do is to see if there are any blank spaces or lines between your PHP tags that come before the HTML.

Its difficult to tell this from pasting the code into the forum.

If you have problems locating attach your PHP page to the post.

Cheers
Ian

like Ian says, it is caused by white space between php tags.

the error is reporting the problem at line 5:
output started at... /httpdocs/siicom_cart.php:5

most likely, there is a blank space at the end of the closing php tag on line 4:
"?> "

see this post for more details on troubleshooting and fixing the headers already sent error:
showthread.php?t=19285

as you saying it was a simple white space! Thanks

that is the most likely cause, but i can only guess.