That site drives me nuts. I'm sure it's great if you've created your page in dreamweaver and can identify the location of the lines of code the same way the page does, but if you're running a site from a template someone else has coded and have no idea how all those line numbers relate to your template, it makes you kooky. Plus it's always telling me that I have open tags when I don't. I threw up my hands a year or so ago.
I did try doing the recommended fixes in CSS, but none of them address the width of a single post and once I change the 0s to 0px, it was even more upset.
I think if I can just find out where in this funky template the width for a single post is, I'll be able to fix it.
Sorry I didn't respond sooner - for some reason my RSS feed isn't working.