I did like the above said and ENB now launches (with the Wrapper version, not tried this fix with the Injector) and FNV runs fine so far. I copied the d3d9.dll that I had for my ENB and placed that in my exe folder, that came with the 4GB. Things like this really get my OCD up so I did a bit of trawling around and found this solution. I know the guide mentions that people have had issues with ENBoost and the 4GB Loader, so I tried the Injector version instead of the Wrapper version as the guide suggests and it still didn't work.
I have recently just finished working through the guide and ENBoost wouldn't launch whenever I started the game.
