optimizer-ZendOptimizerforPHP问题

php页面执行提示：
PHP Warning: Zend Optimizer for PHP 5.2.x cannot be found (expected at './plugin/Zend/lib/Optimizer-3.3.3\php-5.2.x\ZendOptimizer.dll') - try reinstalling the Zend Optimizer in Unknown on line 0
请问大神为什么呢