Ah, wondered where Otto went! I, too, was working on my site when I got the message. I typed the following words “Why is my .htaccess file read only?” into the codex search box, and back came the message: “You have been temporarily banned from accessing www.remarpro.com because of unsavory behaviour on the support forums.” Exactly the same as the others in this thread.
I must admit I was a bit taken aback as I’ve never been accused of that type of behaviour before! Anyway, as I said in my previous post, I can get into the codex now.
Still can’t find an answer to my problem that I actually understand, but that’s another matter…