What is the ruling on money earned from selling computer programs authored using pirated software, and is it permissible for customers to use them? Can he sell more of them after purchasing the original versions of the tools used, and what should he do to correct the error if the answer is no?

The money earned from manufacturing programs through personal effort, even if pirated software was used, is lawful money. The manufacturer would have usurped the benefits of theated software, not the software itself, and therefore owes only the value of these benefits. If he purchases original copies of these programs, he will have fulfilled the rights of their owners. His customers are entitled to use the programs he manufactured and sold to them, and he is permitted to sell more of them.