>Ok, pardon my ignorance, I have it working now, but what I wanted was to cascade all VFP forms in _Screen, not all open windows in the environment (not IE, Word, etc). Is it possible?
>

You've to pass proper hWnd. Try

DECLARE SHORT CascadeWindows IN Win32API;
      INTEGER hwndParent, INTEGER wHow,;
      STRING @lpRect, INTEGER cKids,;
      STRING @lpKids
= CascadeWindows(_screen.hWnd, 0, 0, 0, 0)