I reread this thread, you can't install Sims or lots while the game is running in case anyone runs across this thread. And unless you know how to keep both the disc games and the UC (like I did) it's better to install TS2UC without TS2 installed.
ETA: MTS has a tut about this if you didn't remove TS2 before hand, and not remove it later if you never installed it etc. It can cause weird problems. I would refer anyone to their site to follow instructions of how to install TS2UC if you didn't uninstall TS2 first.