when u click on that radio button, does it get checked?
does your code enter that part MessageBox(blavblabla)?
btw tutorial that u r looking into is a bit old
things have changed, DialogProc returns INT_PTR value (allthough your compiler doesn't say anything about BOOL, it's wrong)
If your code is compiled for x86, it happens that "it works", but compiled for x64 platform most likely it will crash.
so i have no luck to get this work then? :(