The error is "subdivideFace: Didn't split the polygon near: (-815 354 1000000000). No idea what 1000000000 refers to, but -815, 354 is broadly speaking the centre of where the building is (or would be). The error also mentions the texture of the polygon at fault; there's no brush with that texture anywhere near it, in fact with the building removed there's no brush there at all, but still the error.
Any guidance appreciated greatly, as is "do X ajay and it's fixed"
