So, for some reason, every time I enter a world and am about to create a save, the game doesn't load that world and shows me an error saying something like "a serious error occurred while loading this world," and tells me to restart. However, even after restarting, it still doesn't load. I've tried removing all of my mods, but it did not work. I'm reinstalling the game now just to see if it will work afterwards. I had JUST installed the game, too...

Do you mean, that you get that error when you try to load a save file? Or, when you try to save a world?