So there was a SimFest going on and the proprietor would hop on stage, throw that weird little tantrum that Sims throw when they can't walk somewhere because they're blocked (with the little talk icon that looks like footprints with a red slash through it), he'd leave, the performer would come on, do the same thing. Repeat this several times.

Here's the fix! Going to list everything for those who are new.

You need the cheat console: CTRL-SHIFT-C

type in testingcheatsenabled true and hit enter

Now shift and click on the affected lot on the ground, not an object of any kind, not even a rug. Should get a menu with options to build or buy on the lot. Pick either, doesn't matter.

Grab the floor of the stage. The whole thing is a cover laid on foundation and will all move. Should have weird little X marks here and there (these are marks for where props and people go; keeps us from cluttering up the stage so our Sims can't perform)

Move the floor. Might need the cheat console again if you can't find anywhere to put it down; type in moveobjects on and you can put it anywhere. Don't delete the floor, it's a real bitch to find in the catalog.

I found a weird gray-blue oval 2 spaces long sitting there under the stage floor. I can't remember the name exactly, it was all run together and ended with TwoPeople. Grab that sucker and delete it. (Or have some fun and put it somewhere just to watch Sims get all flustered, like the entrance to a bathroom. For you sadistic types, stick it in your family inventory and use it to kill off houseguests by trapping them somewhere.)

Put the stage floor back exactly where it was.

Back to live mode. Should work fine now.

I still have no idea what that oval is or why it randomly appears under the stage and lurks there to screw up performances. Anyone else been getting this thing? If not, I look very stupid right now.

TL;DR: move the stage floor and 86 that weird oval shadow hiding under it