Menus and Header image appears on right in Firefox =wrong

Hi!

I have a problem with my site not displaying correctly, after I set up a custom URL to the site; www.carrascodance.com the Menus and the Header image appears on the right site when it should be centered.

It works correctly in Google Chrome 21.0, Internet Explorer 10 and iOS Safari but all of a sudden they appear to the right in Firefox Nightly 17.oa1 or Safari 5.1.7

I've also noticed that when I try to press the thumbnails in Internet Explorer, nothing happens it just keeps loading.

I use Win 8 but I got notified of the problem users on other OS as well.

Thanks

Martin