Hi Telle,
Thanks for the pointer. I checked the site and went into a panic - you are right, all of the articles are blank!
But it turns out that the articles are still there (in fact, if you log in and "edit" an article, you will see the content come up in the editor).
But previewing the article and viewing the article don't work, so don't try saving any changes just yet.
It turns out that the version of the Wiki package that is running is so old, that an operating system update that took place underneath it broke it.
The only solution is to update the wiki software itself, something I haven't done since 2011. I don't know what updating such an old wiki will do, but it is the only choice at this point.
Off to adventure!