I did not change anything!
you posted a post (that is a change as well)
the same sidebar problem shows in the single post view of the latest post;
also reflected in the validation report: http://validator.w3.org/check?uri=http%3A%2F%2Fwww.paulinebjones.com%2FBlogWP%2Ffriday-vid-and-some-alien-links&charset=%28detect+automatically%29&doctype=Inline&group=0
Line 49, Column 427: end tag for "div" omitted, but OMITTAG NO was specified
using the html setting of the post editor, double check the content of that post for unmatched divs;
particular this line:
<p><div><a href="http://www.paulinebjones.com/BlogWP/wp-content/uploads/2012/08/anabananazombies2.png"><img class="aligncenter wp-image-540" title="AnaBanana Bath & Body Treats" src="http://www.paulinebjones.com/BlogWP/wp-content/uploads/2012/08/anabananazombies2-300x136.png" alt="pauline baird jones, author, writer, romantic suspense author, science fiction romance author, steampunk" width="180" height="82" /></a></p>