PHP code cannot protected directly. You have to extract important code parts from PHP and place the code into a DLL. Then you protect the DLL with Licence Protector. The DLL can be written with any compiler. If you would directly address the Licence Protector DLL, a hacker could remove the DLL commands.
How to reference a DLL from PHP see http://www.php.net/manual/en/ref.com.php
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