So, a new bug is stopping me from playing almost at all. I uninstalled the previous update I had (6.3.7) from the in-game mod menu, deleted it from the mod folder in %appdata, replaced it with 8.1, and installed that via the mod menu in-game. I now get this error every time I load. 
And when I go out of the town and travel almost/look for a fight, the text never changes and I can't see what I've encountered, and this error comes up.
And when I try to fight, if the enemy is "Lone Stranger" then I get this error repeating infinitely along with no combat options or even the ability to end my turn.
EDIT: So apparently, the problem with fights only happens around Wimborn. Tested in Frostford and it worked just fine. Might be because I fought so much around Wimborn, I'll test out passing a few days to see if this changes anything.
EDIT 2: Turns out passing 7 days does nothing for changing up the people around the city.
EDIT 3: When I start a new game, everything seems to work correctly. Must be something with the area around Wimborn and the amount of people I've fought there. I recovered by reverting to a save game I had backed up from a few days before the saves I was using, so not a ton of progress lost, but I hope my report helps iron those out.