Single Post Error on Blog

One of my sites is acting up. The newest post will show up just fine on the blog page: http://www.commuterservices.org/blog

But it will not show up on the single post page: http://www.commuterservices.org/2010/07/going-off-the-grid/

If you try to view any other single blog post you don’t encounter any errors. Also, this post is viewable via the RSS feed.

Can anyone offer assistance?

–Andrew