Different Header based on landing page...one database

[forced]

If i use this code on a test page to display the landing value it works fine.... but when I tried putting in on the index.php page of zen... I got an error: Fatal error: Call to a member function add_current_page() on a non-object in D:\Inetpub\energetixjewelry\shop\includes\autoload_func.php on line 90

if (!isset($_SESSION)) {
  session_start();
}