I have a pretty basic site set up with few modifications done to the original template. Everthing looks fine, but if you click on the title of a post to read it by itself, the right sidebar moves to the left sidebar position, and the left sidebar moves to the middle, under the comment box. Here’s what I mean:
if you haven’t changed the php files, the problem is with the original template.
If you want to change the right/left structure, just look at the structure of index.php.
Or you could go for another template. 🙁