include( $_SERVER['DOCUMENT_ROOT']. doenst work

Hello,

im trying to get my pre-generated webshop to work. In this pre generated webshop site it says i have to use 2 kind of codes, the first i have to include the code where i want to show the shop:

<?include( $_SERVER['DOCUMENT_ROOT'].'/argeweb/webshop/index.php')?>

And the webshop says litarelly: “Before the headers are sent paste the following code:”

<?
include( $_SERVER['DOCUMENT_ROOT'].'/argeweb/webshop/shopstart.php' );
ob_start();
?>

I have Added the code on the top of my header.php file.

Now the shop is visible, but all the links in the shop don’t work, and i think it has to do something with the second code i have to add.