Cannot edit or create new posts

For this blog: https://www.americanfreethought.com

I upgraded to 2.7.1 today, but now if I try to edit and existing page or post, I get a popup with this message: “Internet Explorer cannot open the Internet site https://www.americanfreethought.com/wordpress/wp-admin/post.php?action=edit&post=230. Operation aborted.” And then it boots me to a page that says “Internet Explorer cannot display this page.” (Obviously the URL is different for each post.)

Any ideas? Thanks!