I haven't looked at the complete code, but I think you can use something like:
PHP Code:
if(isset($_GET['cID']) && ($_GET['cID'] == $notes_active->customers_id) && !isset($_GET['gID']) ||(($notes_customer_result->RecordCount() > 0) && ($notes_customer_result->fields['customers_id'] == $notes_active->customers_id)) && !isset($_GET['gID']))