In order to run it, please install the freely available Zend Optimizer, version 2.1.0 or later.
What is the Zend Optimizer?
The Zend Optimizer is one of the most popular PHP plugins for
performance-improvent, and has been freely available since the early
days of PHP 4. It improves performance by taking PHP's intermediate
code through multiple Optimization Passes, which replace inefficient
code patterns with efficient code blocks. The replacement code blocks
perform exactly the same operations as the original code, only faster.
In addition to performance-improvement, the Zend Optimizer also
enables PHP to transparently load files encoded by the Zend Encoder or
Zend SafeGuard Suite.
The Zend Optimizer is a freely-available product from Zend Technologies. Zend Technologies is the company that develops the scripting engine of PHP, also known as the Zend Engine.