game wouldn't launch and now says i don't own the enchanted by nature pack.

miychou​  Please load a new save, for comparison's sake, and let me know how much of the new expansion's content shows up: fairy wings, other CAS items, the new world, etc.

For your existing save, are you saying the game crashes when you select the save, or after you load into your main household, or some other time?  If it only crashes once you've selected your household or clicked Resume, please you use Load Game to choose another household and see whether you can load into that.