Constant loop between /wordpress and /root category after update

Hello.

I’m trying to publish a wordpress blog that I’ve built for a client and I’m having a problem after updating from WP 2.2 to WP 2.6.
The blog worked fine when I first installed on the server (hosted by: XO), but after updating it to 2.6 (with WordPress Automatic Upgrade) only the adminpanel works.
When I try to access the blog through http://www.rosenworld.com/wordpress I think it’s pointing back to the root, http://www.rosenworld.com, which is META-refreshed back to http://www.rosenworld.com/wordpress/index.php putting me in a constant loop.

Anyone who knows what the problem might be?

It’s probably something very simple, but I’m kind of new to WP and the whole database thing so please be patient with me.