How to Just turn off Categories on Front page ?

[gjh42]

Umm... you were supposed to put the parts in the places I described, not just paste the whole thing at the end of the file - that does nothing.
The
if (!$this_is_home_page) {
goes in here:

 * @version $Id: categories.php 2718 2005-12-28 06:42:39Z drbyte $
 */

  if (!$this_is_home_page) {

    $main_category_tree = new category_tree; 

and the
}
goes where you put at the end.
The comment
//the module processing code
is a placeholder for all of the code in the middle of the file, not literal.