I actually found out the problem with the help of a friend. It was so simple! Whoever created the template added a div tag to EVERY .php file so it was pulling the #main info twice, hence the double borders.
D’oh!
Thanks for the help though. 😀 (And the comment!)
I tried that it just turned it into a fluid-width format… with the double borders, haha.
The only time I see the DOCTYPE declaration is on the header.php file and there’s nothing before it.