More info is needed. That fact that the default index controller works suggests to me that the problem is not with your rewrite, but that you are not entering the URL correctly to route to your controllers, or that you are naming something incorrectly.

What is your file structure, what are you using as the URL for a controller that does not work, what are you using as the URL for the default index controller, what are you using for the class name of a controller that does not work, etc...