Okay look, i had this error before, but i know how to help, so just re-download the mod, unzip it, but don't take the .exe file out of the folder its in, there's this little thing named data in the same folder, the exe file uses that data to run the game, it'd be easier if you get UTMT so the Data file has a little special picture of either the blue soul with legs or a peppino hat with legs, so, keep the exe file inside the folder it came in, dont delete any of the other files in the folder, keep it the way it came in, except the .zip part, you can unzip it