Sims 3 Pets Appaloosa Plains Glitch

I recently installed The Sims 3 Pets and Late Night, and have been having serious trouble with Appaloosa Plains. I have been able to play, but always in the course of me playing the game freezes, and then I can't do anything and have to quit the game. I havent really had this trouble outside of this neighborhood. Can anyone help me? I really want to be able to fully explore the new neighborhood!