CSS Tweak - Some css not displaying properly in Firefox.

I purchased a website theme (html/css) to use as the basis for a company website. I've been working on it for a couple of weeks in Dreamweaver. When I Preview In Browser while in Dreamweaver, everything displays perfectly in all browsers. I FTPd the site files to the server yesterday to go live, and now the site is only displaying properly in Internet Explorer. The element that is not displaying is the background of main.css. The way the site was designed, there is a dark colored background image in the body/wrapper, then below the navigation, in the content section the background is white with a fixed ribbon image and a javascript rotating slider. This entire section is what is not displaying. All of the text, buttons, and content is there, but the white background isn't showing so the darker text is impossible to read. The site displays correctly in IE, but with this missing div main css in Firefox, Opera, and Safari. You can preview the site at [login to view URL] to see the display issues. I attached the files that I think have the problems. If needed, I can also supply the original html/css code. I can also attach the code in a different document type, if needed.