I feel extremely dumb, but I simply can't get it to work.
What I've done is :
1) Download Demaster.
2) Put all Demaster files in my FF8 Remastered folder.
3) Run Demaster so it unpacks everything.
4) Download some mods. (LunarCry remastered for example)
5) Put the whole "texture" folder from .rar/zip mod archive into the "texture" folder from DEMASTER_EXP
6) Run the game.
And I get the "unknown error". Some features will also cause other types of error, such as the UV mapping that tells me "Addresses are wrong. We found no ADD byte ptr[esi+8] at given rel call".
I don't get it, since the files in my FF8 folder look exactly the same as on Light's screenshot a few posts earlier. Same path, same files, etc. I'm new to this, so obviously I must be doing something wrong :/
I have also tried to tick/untick options one at a time, to see if one of those was causing the error, but it seems all of them are causing problems and will prevent the game from launching properly. I mean, sometimes I'll get past the "press any button" screen, but right after that I'll get an "unknown error", so... yeah.
For the sake of it, I've also tried with older versions of the Demaster, but the results are more or less the same.