GAC and DirectDraw help

Question

i've downloaded a tutorial sample application which uses directx. but every time i want to compile it: " couldn't find Microsoft.DirectX.DirectDraw ... etc are you missing a reference?". the .Net Framework is properly installed and so the directx sdk 9.0 is. when i open the GAC i can even load the direct draw assembly, but nothing happens neither it won't be added to the assembly list nor i can compile the application.