I messed around with the Advanced Settings of the fb app (which also has changed quite a bit since the screenshot in the Install Instructions). Once I enabled “Disable Deprecated Auth Methods” and “OAuth 2.0 for Canvas” (previously I had them disabled), the app seems to be working. I’ll let you know if I have any more issues.
Just realized I forgot: the location of my WordPress blog is:
http://vistateach.biz/