Hello there!
So uh regarding the file0 you see in this zip with the updated data.win file well there is a softlock with Papyrus's geno fight but it should be fixed! However if it isn't just replace the file0 in the localappdata of Undertale with the one in the folder since it skips it if the softlock has prevailed thus you can continue the geno route. DO NOT REPLACE THE FILE0 IF YOU ARE DOING PACIFIST OR NEUTRAL! It is only meant for Geno as I will have a newly fresh file0 for Neutral (If you plan to kill Papyrus.)
Anyways that's all and thank you for downloading the Error mod and thanks for reading this here note.