Try clearing the system cache from recovery mode and the app's cache and data from the application manager in the settings menu. There are dozens and dozens of threads about this if you need any elaboration.
Failing that, you need to provide a lot more information if you want good answers. At a minimum tell us exactly what changes you made to build.prop, what S5 model you have and what your firmware version you are using. And anything else that is even remotely pertinent e.g. verbatim error messages. It would also be in your best interests to do a search to take advantage of the wealth of information in existing threads and enable you to pose more informed questions.