why does not $zco_notifier->notify(...) work for ipn_main_handler.php?

[linjuming]

why does not $zco_notifier->notify(...) work for ipn_main_handler.php?
I am sure that my code works in usual pages , such as when I pay with moneyOrder, it will create a xxxxx.txt at basehost.

\includes\classes\observers\class.observers_linjuming.php codes:

<?php 
	class observers_linjuming extends base{
		function __construct(){
			global $zco_notifier;
			// $zco_notifier->attach($this,array('NOTIFY_CHECKOUT_PROCESS_AFTER_ORDER_CREATE'));
			$zco_notifier->attach($this,array('NOTIFY_CHECKOUT_PROCESS_AFTER_ORDER_CREATE'));
		}
		function update(&$class,$eventID){
			// 添加或插入用户积分
			if($eventID == 'NOTIFY_CHECKOUT_PROCESS_AFTER_ORDER_CREATE'){
				file_put_contents('xxxxx.txt','dddf');
			}
		}
	}

\includes\auto_loaders\config.linjuming.php codes:

<?php 

$autoLoadConfig[1000][] = array(	'autoType'=>'class',
													'loadFile'=>'observers/class.observers_linjuming.php');
$autoLoadConfig[1000][] = array(	'autoType'=>'classInstantiate',
													'className'=>'observers_linjuming',
													'objectName'=>'observers_linjuming');