Ah, interesting. That’s the first time that’s happened. Its a combination I wasn’t expecting.
Pretty sure I know what is needed. I’ll get back to you tomorrow with a solution.
As an aside, and more for general information than you specifically- its not actually a good idea to install kiwitrees (or webtrees for that matter) in a new location but still addressing an old database. Especially not if that database is your main one.
During many upgrades non-reversible changes to the database are made. That is the case this time. It may be fortunate that you had that error, otherwise changes will have been made that would have rendered your main site unusable.