Earlier today, Cat had mentioned a useful cheat on Crinrict's blog that helps with placing lots and correcting if they sink or elevate. I was facing that particular issue, because the world I downloaded doesn't have a lot of large lots and Cat's lot I wanted to use was gonna be a bit weird.
So I checked it out and then looked at a few other helpful tips and such while there. In particular there were a few houses that would not get back in game through the launcher. It wasn't the launcher, it was the sims3pack files themselves.
The tip was to convert them to .package files and add them to the library. My lots have been recovered, thankfully. I saved them fresh, with a few minor adjustments because I built them ages ago and deleted the library files of the old ones. I am just soo relieved that when I remove the old ones, I still have them. I'll probably retweak them, but soo happy!
My Name is LE or LE Style. I have a tendency to go off on tangents from time to time. Such is the MADNESS of my Mind.