I have the same error on the index page at http://www.amyloo.com/clipoftheweek
Like one of the first posters in this thread, it happened after I added a query_post — in my case to exclude a particular category of posts from the index.
Like the just-previous poster, I isolated the troublemaker. It’s the theme; when I revert to the basic theme, the error goes away. Problem is the thememaker says my question is beyond his scope of support http://forums.wpthemes.info/comments.php?DiscussionID=126/
So now what? I’ll likely end up starting over with a new theme based on the default rather than modifying a theme that doesn’t look anything like what I ended up with anyway! But for a quick fix, I thought it might be worth asking if anybody has any ideas. Thanks.
/amyloo