Thanks for responding Daniel. The problem continued after I deactivated Edit-Flow (the message blamed update.php instead of an edit-flow file), so presumably it lay, or lies, somewhere else.
I *think* I might have fixed it by screaming at full voice and deactivating every plug-in except anti-spammers and an events calendar that’s chock full of data. The scream was because I’ve used a plugin for backups and it wouldn’t complete, which means that I couldn’t update WordPress, which means….
Anyway, I can now preview a post, which is progress, if it continues.
Thanks again.
