Some umpteen years later, this problem popped up. I'm trying to extend a basement on my lot. It has no platforms and I was able to build the basement. I've played other lots, returned to this one and this 'Can't find object' came about once again. Can't extend the roof. Basically, anything having to do with build are unable to work.
The lot is part of my base game in Glimmerbrook, Brooks Bridge Borough. None of the other lots there are affected like this.
I exited the game, started it again, and went straight into Build mode for that house. I was able to extend the basement and any other build tool I wanted to use. Went back to Manage Worlds, and entered the house through the family. That worked.
