Long story short: you're wasting your time.
It's trivial for a well-informed person to copy your code. If you don't trust these people, you shouldn't be working with them.
There are no technical ways to make your code safe, as it must execute on the host system. Work with good people, write contracts (if you must), and move on...
Update: I forgot to mention, if perl2exe works like PAR does (which I think is true), did you know that you can open that .exe file with WinZIP? Please, spend your time on productive things.