Exactly the same here. Houses furnished or built with custom content don't load. The loading screen keeps turning for hours on end, but to no avail.
Ah jeez. That's what happened when I installed FT last time..
Remember, before installing a new expansion, MAKE A BACK UP OF YOUR GAME OR YOU WILL LOSE IT IF YOU UNINSTALL. I made this mistake last time so don't let it happen to you!