[Endoperez]

Which spell gave you that message? If the game crashes because something tries to use the spell that doesn't exist any more, you might get by by changing whatever it is that causes the message. Unless you used Holy Pyre it can't be an item IIRC, ritual summon spells can't be #onebattlespells and probably won't be referenced by units, and if it's the nation itself that's calling the spell, it might go away by #selectnation, #clear.

I hope it's that easy. You have interesting projects, and it'd be a pity if you couldn't complete them.