I checked the description page and they are mentioning an ENB series version 0.121 I'm using version 0118, since is the one stated by Midhrastic ENB of FO3.
Check if the files you put in your FalloutNV folder are the correct ones. You only need the files that come with the blackout ENB version you choose + the d3d9.dll (only that file!!!!) provided by the ENB series file contained in the link mentioned in the description page of nexus (). The issue was the files I put in the FalloutNV folder (where you have FalloutNV.exe).
I remember to have had that problem when I first tried to use ENB mods with the vanilla game. I've also used Midhrastic ENB from FO3 and aside from the performance loss nothing bad happened (Midhrastic is hard regarding to performance, but its' really worthwhile). I've tried two different versions and they didn't have any problem. I'm using Blackout ENB at the moment and it works fine.
