Have you checked the functions.php of that theme? Maybe there’s a cancellation of the default get_sidebar(); function and a redefinition of it, where it includes both sidebars.
Ok, i have a problem too. I have exported my posts from lancevance.wordpress.com to http://www.lancevance.org but now the authours of their comments aren’t showed. But if i write a comment from there, author is shown, so i assume problem is in XML file? Oh, btw, if i look in the source code i see that the authour’s name is commented; like that: <!–[CDATA[authors_name]]–>
