Thanks Abwayax. It's now possible to use 'search wiki'. Great!
Previously I encountered a white screen problem when creating new pages, where the wiki doesn't return you to the page that you edited.
I think you may know about it, but I thought it would be best to mention it. Now when I create or edit a page, it brings up this. However, note that I'm temporarily using a different computer and browser (Firefox instead of Chrome):
(May I ask, what do other people get?)
Also, when I delete a page there are no problems. It works expected with a 'Return to Main Page' message with a link to the main page. Moving a page is fine, too, including the process of moving a page into an existing page (deleting the old page and leaving no redirect at least).
There is a big problem that you're probably aware of too. The database contents pages are empty and apparently only the text that exists in edit page's box remains for the individual entries.