The Sims 3 keeps crashing when I change a fireplace

Hi, I have currently been playing the sims 3 university but the game keeps crashing. I moved my sims family into the modern victorian house in moonlight falls which was already built. I then started decorating the house to my fancy but then discovered that there seems to be a glich on the second floor of my house that causes the game to stop working and shut down. This happens in the front bedroom on the second floor where the fire place is, I delete the old fire place then pick a different one and place it in the same place as the old one, as soon as I do this the game crashes. I can keep playing the game without changing the fire place but this is a problem. Can someone help!!!