Stuck on Building lot screen and can't close the window

@FairClarity  I'm glad it worked out (mostly) in the end.  Let us know if you have any more issues.  And from now on, I'd suggest placing any Gallery lots you want to use in a new save first, so you find out whether they're broken without risking damage to your main save.  Many lots broke after the pre-For Rent patch, and some after that.  It's impossible to tell which ones are affected without testing them yourself.