If you downloaded all the files from the Itch pages very recently and at about the same time, there shouldn't be an issue with the versions being incompatible with the main game. If you're not sure if you got the files you have at the same time, deleting everything and redownloading them again could help. It's also possible a virus scanner is blocking the files or that the game needs more space to properly run even if there was room to download the files. I'm sorry for the trouble.