You dont need to set the paypal url as its sent automatically by the module.
All you need to do is follow the instructions in the install file... its one of the easiest things to install in the world.
This contribution does not install any extra pages its a drop in module that requires no core code changes. So its likely you installed a different IPN module.
You will more than likely get a better response if you dont hijack threads with un related questions.
I would suggest that you start a new topic which is specific to your problem.