"Next" button in installation path wizard window

Hi All,

If I choose default installation path which has disk space zero bytes and execute my installer than even if i change the path the next button is no getting enabled. What change i need to make to that I can make the "next" button Enable?

Are you sure the new path you type is completely valid? I don't see any piece of code that could cause this. The Next button has no memory and the free disk space is recalculated for every installation directory change.