windres is part of fpc (and should be located inside its platform dependent directory), in my particular Free pascal specific case: G:\WinDev\FPC\3.0.0\bin\i386-win32\windres.exe
Since you've installed Lazarus 1.6 (assuming release candidate there), you should be able to find it inside your FPC (3.0) directory.
When you started lazarus for the first time, was it able to find you fpc and fpc sources directory ?
Other then that, i don't think it is necessary anymore to use the include solution you presented in your code.