Someone

	if(($del_addr == "")||($del_postcode == "")||($trees == ""))
	{
  echo "<meta http-equiv=refresh content='0;url=add_order.php?selecterror=Yes&trees=$trees&cust_order=$cust_order&inv_addr=$inv_addr&del_addr=$del_addr&inv_postcode=$inv_postcode&del_postcode=$del_postcode&cust_id=$cust_id'>";
  exit;
  }