Horizontal for whole page - where does it come from?

After removing a few additional widget areas and fixing others, I found my website with a quite big horizontal scrollbar at the bottom which moves the content left/right. I have no idea where this comes from as I have not changed anything about the layout and I am unable to detect the reson with Firebug.

I DO have two header-widget-areas although I deleted them and I do NOT have any code for that in anywhere so they should be gone but they aren't. I have tried everything but those have been around for quite a while (they have been duplicates before I deleted them today but now they are still there, although technically no longer duplicates. Maybe there's been a problem with that? I don't know.

The URL is www.urgeschmack.de - you will see the scrollbar horizontal right away and I would be very thankful if you could help me remove it.