Sidebar appearing below footer

I've been using the free Catch Box theme for quite a while now, and I love it. However, I just noticed that the sidebar has started appearing underneath my footer on post pages. It's fine on the home page (http://goodchurchwebsite.com) but it's not right on post pages, like this one: http://goodchurchwebsite.com/martin-luthers-sacristy-prayer/ I assume it's something simple related to CSS, but I don't know enough to fix it, and I'm not sure how it got broken...help? Thanks!