After encrypting PHP Code with Zend Guard 4.0.1, it is always not working properly. Solution Ideas

After encrypting PHP Code with Zend Guard 4.0.1, it is always not working properly.
I am from the Internet to find Zend Guard 4.0.1 cracked version, after encryption, run is always not normal, do not know is not cracked version of the reason, I would like to ask everyone usually encrypt PHP code, are used by what tools?

------Solution--------------------
Zendencoder
But it's a charge.
Php_screw
This is open source, you look for it.
------Solution--------------------
Do not select the highest encryption when encryption, check and so on encryption.

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