I'm feeling much better about things. I managed to import the data from this forum (data exported Aug 5, 2021) and import it to a fresh install, and it seems to have worked. I didn't import everything, but it looks like it does work.

You can find it here: http://formosahut.com/fh_forum2/mylittleforum-2.4.24.

So it looks like if this forum, which has been going for nearly ten years I think, breaks, I'll be able to rebuild it quickly.

I might delete that above forum after a few days. I'll play around with it a bit first.