Hello. I ve got same system and same non-steam Vegas as OP. I had the same error on several mods (Project Nevada, Cinematech, Director's Chair and some others). One of them fixed after installing FNVToolkit. For others I tried downloading manual versions and installed them via NMM. Install went fine but after that Unified HUD project crashed with the same error. Then tried unpacking .fomod files to vegas\data folder - same error in Unified HUD. And then tried usual NMM installation of these faulty mods again and that's fixed the problem. Summary: - If this error occurs unpack mod file from Nexus Mod Manager\FalloutNV\Mods to Fallout New Vegas\data - Install normal way via NMM, hit "yes to all" when asked. This way i fixed all mods except Project Nevada, somehow it's not working for it. Manual install went fine though and Unified HUD detected and installed fine. Leaved it that way, don't want to experiment anymore. Hope this helps.
