DirectX 9 -- Assemblies not found only when pre-compiled?!

I downloaded a C# DX9 game, the binaries. It doesn't run. Tells me it's missing the Microsoft.DirectX.DirectDraw reference. So I download the source code. I run it. It works. I compile it, and try running from the .exe file. It works. What gives? I know I have the files, because the game runs when I have execute by source or when I compile it myself...