SDL.dll not working

[FrostyAshesGames]

So, originally, I got Amnesia through the Humble Indie Bundle, but that version broke so I decided to buy it through Steam. I was going through the White Night mod at the time the game broke, and now that mod isn't working. No mod is working actually. And I went in to try the actual game, and that works fine. Every time I try to open a mod, it says the program won't work because the SDL.dll file is missing, but I've checked the Amnesia files, and there's two SDL.dll files there.