Please let the Sims move and live on the 64x64 lot.

Which one? If you’re talking about the ones that are usually parks, you can level the lot and build on it. Just change the lot type to residential, and you can move in. If you still want a park, you can build one on a smaller lot. Some lots, like the park in City Living, are Special venues that the game uses for gameplay functions, such as festivals, so they can’t be altered for that reason