Need advice: PHPBB / FireFox

Just installed PHPBB on my website today:
http://winbreak.com/forums/

Did the most basic of changes to the header and footer. However, now, the thing won't show up for Firefox users in any sort of semblance of what it should look like. IE7 appears fine.

Suggestions, anyone? Thanks so much!

Nu

I think you might have removed some scripts.

How did you implement these changes? In the CSS? In the HTML?

...and in what files? Did you use the built in editor, or hack it up on the backside?

It looks as though there are enough errors in your output that FF isn't rendering it with styles.

You've got several redundant closing tags in the output of the main page.

Thanks for getting back to me, guys, I appreciate it!

I used the built in editor. For the footer, all I did was add my URL to the footer (next to the "The Team" link).

For the header, all I changed was the "Title."

Those were both modified in the "Overall Header" and "Overall Footer" files using the built in editor.

The only other change I made was a CSS modification (again, using the built in "Style editor" to center the banner at the top of the page... changes seen here:
http://www.ktuk.net/phpBB3/viewtopic.php?f=32&t=3637


Could a single "</div>" tag in the wrong place be causing something like this?

Thanks everyone!