Round up post:
It was originally "TabletopPornstar" and then the Dev changed it to "Bornstar" to try to avoid Patreon/Itch.io issues.
Becoming a "Porn star" is one of the planned endgame routes, but there are like 6 or 7 other outcome routes too, so the change is actually not entirely misleading.
Yes, it's a known issue. I've advised the dev how to fix it for future releases but it is up to him.
The way to solve it for an existing save game is written in this post a few pages back:
https://f95zone.to/threads/tabletop-bornstar-v0-65-basilicata.75111/post-12163550
Note that you'll need to modify what variable you add depending on the error you encounter, the missing variable is listed in your specific error trace.