Atom / RSS Feed problem since WP 2.0

I just upgraded my blog to WordPress 2.0 and I have this weird problem with my Atom feed. Each of my last 5 posts repeat the last 4, 3, 2 and 1 articles that is feature on my main page. I have cloned my SQL database to check if this issue would repeat itself on another directory, and it doesn’t

Look at my problem here : http://laurentlasalle.com
Look at my subdirectory that works here : http://laurentlasalle.com/inprogress

I don’t quite get how RSS works in WordPress. Please help?