Hi, I am playing the playstation version of the game (The Sims 3) and I have moved into just about every house available before. The two versions are nearly the same. What is the address of the house that you are trying to move into?
Make sure you have enough money for the house. Clear your sim family's inventory, sell anything you don't need. If you have too many items in there (such as books, old newspapers, fruit, insects, etc.), you will be prompted to sell them or delete them before you can arrive at the new place.