Everything works but comments

I just installed and upgraded WP and after some minor problems everything seems to work–except comments. When I try to post a comment I wind up with a blank page.

I checked my options and made commenting as wide-open as I could, but no luck. I had some issues with folder permissions due to upgrading, so that could be a factor. Check it out and let me know what you think.

http://esotericteaching/wordpress