Crash,Crash,And crash

[Mudbill]

But if you crash at a point during a custom story, you must contact the author of that custom story. We can't fix their issues.

Now, seeing as you've modified your game, that might be the reason. Even if it helped you run it, the older version might be missing something the newer game requires. I'm sure there are other threads around here on how to fix this SDL.dll issue.