Posts won't display in categories

I recently upgraded my blog – My Mommy’s Place – to 3.1.3. My posts are not showing when I click a category. The categories show up at the bottom of each post as well as in my sidebar along with the number of posts in that category. But, when I click the category link, it displays, “Sorry, no posts matched your criteria.”

I’ve tried resetting my permalinks, but that didn’t help.