Lua Error from using "Creature Display" in classic HUD

[Taco]

I am using the "Classic" HUD and I accidentally turned on "Creature display"/"Toggle list of seen creatures" with control+tab, then saved and quit the game. Upon loading it gives me this error. I fixed it by turning on "Minimalist" HUD and then turning off Creature Display. I easily reproduced it trying to figure out what happened and save my character.