This is what we call a game.dat crash. The game includes a primitive crash debugging system which can pinpoint many crashes, but sometimes the crashes are not detected by the debugging system and as a result you get the error message that you see now. There is no way to tell for sure what is causing your game to crash. Your best option is to try and revert back to the latest working version of your mod. Try to undo things you've done until it works again, and then proceed forward once more.
Sorry that it's not a good answer, but these sorts of crashes are very frustrating because it's extremely difficult, sometimes impossible, to identify the cause. You just have to muscle through it.Go to the full post