hmm will try to fix that, but could You check whether:
is NV running in emergency mode?
does other effects work?
is NV running as x32 or x64 (if You are using x64 system version)
does Your system support Microsoft DWM Thumbnails (or simply asking can You see window thumbnails when hovering over taskbar task etc.)
also does effect doesn't work at all - or there any symptoms it does something (blinking, disappearing windows etc.)