If you click on the date stamp at the bottom of this entry you'll get taken to the individual archive for this entry.
The layout is basically a reproduction of this one, complete with both side bars.
If you click in the Comments link you'll get taken to the comments entry page which has its own layout, basically a reproduction of this central column.
From the comments entry page, you get taken to the individual archive but this time the width of the window is restricted to a width of 480, completely buggering up the layout.
Humph!
A test comment because I think I've resolved the issue. I edited the JavaScript in the HEAD of the index page so that it wouldn't pre-determine the width of the window used to enter the comments.
That way, when you get sent to the individual archive page it's not buggered up by the window size.
A second comment to test the layout of the comment preview page.
Good job, I think it all looks great!