I didnt have the original csharp file, but I just found an alternate solution.

I went to my steam and went to properties, local files and clicked "Verify integrity of game files" and it seems to have worked. Thanks for your help though :)

I downloaded the MiniSavestates mod in resources to practice Path of Pain. But I also want to play on my casual save files without using the mod and Im not sure how to remove it or at least disable the mod. Can anyone help me with this?