[SOLVED] Home Button Going to /blog

Disclaimer: I am just a librarian who wanted her library to have a nicer website so I decided to do it myself. I am aware that there are CSS errors in my site (just discovered the CSS validation service and am slowly learning about all that) ... but this problem just began yesterday.

Yesterday I updated both Wordpress and Atahualpa to WP 3.4.2 and Atahualpa 3.7.8.

My site used to work so that when you typed in http://www.franklinlibrary.org you would arrive at our site and the home page was our most recent posts. When you clicked on Home in the page menu, you would go to http://www.franklinlibrary.org

Now, clicking on Home sends you to http://www.FranklinLibrary.org/blog, and you see an error that the page doesn't exist. However, when you remove the /blog from the end, all is right.

How do I make it so that clicking on the Home page in the menu bar takes you to http://www.franklinlibrary.org, and not http://www.franklinlibrary.org/blog ?

Things I've explored:

- deactivated all plugins
- when I switch to Twenty Eleven theme, the home button works (that is, it takes you to http://franklinlibrary.org and you see the posts)
- in general settings, the correct URL (http://www.franklinlibrary.org) shows in both WP URL & Site URL
- in Settings >> Reading the front page is set to Your Latest Posts
- in wp_config.php, define wp_home and define wp_siteurl are both set to http://www.franklinlibrary.org

Thank you in advance for any assistance (and for such a lovely theme).