it's to my surprise, too, search out this:
http://stackoverflow.com/questions/11584109/load-zend-optimizer-for-php-5-3
"Zend Optimizer doesn't exist for PHP 5.3.
The product was renamed ZendGuard when it was released for PHP 5.3. However, ZendGuard cannot load files that were encoded for Zend Optimizer, and vice versa -- they're effectively two separate products. If you've got an application that was encoded for Zend Optimizer, you're stuck on PHP 5.2."
hope this can answer your questions perfectly.
