Thank you, Drew! At first, I got only a blank page when I clicked on Themes (which was at least arguably better than an error message
), but after I saw that there was an update to Wordpress itself, I installed that and the Themes page appeared. I was able to then successfully install a new theme.
When you get a chance, could you please give me a quick response to my other thread about mixing WP and non-WP pages? The domain you fixed for me is not my main one; I'm just using it to experiment with WP. Then I want to switch the home page and a few other pages on my main site to WP, but without affecting the less-important pages that can stay in hand-coded HTML. Thanks!