Like I said I doubt that is the reason, however it is worth trying on a fresh database just to eliminate all possibilities. Maybe because an item is saved at a position that doesn't exist on your map (since it is only 14,000 by 14,000). Ofc do not delete your old database, just make a new one and try it.
Edit:
If by some miracle a fresh database does fix it, then load up the old database and just remove all items that are on tiles outside of your 14,000 by 14,000