I'm sorry people copy your stuff.

I'm not one to tell someone else how to run their business but could it be that relying on fragile concepts such as "Intellectual Property" are not a good method for gaining the ability to control and profit from your labors?

Personally I've always relied largely on the reputation I've built up for being able to solve the problems of my clients but your mileage may vary.

I hope you find a solution to your problems, it's not fair if you work really hard at something and get nothing back for your effort.