Thanks for the download. I also get crashes with this message while building the house and switching to final stage, but only sometimes. Looks like a pathing issue happening in certain cases when pathbits are applied / the building gets done.
After cleaning up points in your fbx, it did not crash anymore building all 32 variants in a row. I removed use_002 and moved use_001 to an accessible position on the road in front of the house at (0,-3), build points also moved to the road at (-2,-3) and (2,-3). In general, the game can handle bad points and people just go there through forbidden tiles but it might make problems. So I always put use-, create- and build-points on accessible tiles defined in map section. Hopefully that solves it not only in my test.
