Sidebar after posts in the index

Hi all! This is the blog: http://www.stabaccati.centallo.com register on dreamhost server. I have some others blogs on dreamhost but this came directly from the hell.

I use blog with some friends and now we enter just few posts, as you can see. I don’t know why, but now the sidebar is shown after the posts. It happens from nothing a without modification. I tried some thing without success:

1. Upgrade to the version 2.0.2
2. Change theme, but of the defaults installed just the theme of 1.2 wordpress works.
3. Deactivate all plugins
4. Delete cache of browser and change browser
5. Remove the sidebar from index, but the sidebar just diseapper and the blog is always “moved”
6. Removed the cache of WordPress

Really I don’t know what’s happening. I don’t know what to do anymore. If I reinstall the problem isn’t solved because after some posts there is again. Can anyone help me? Is a bug of wordpress?

Note: If you click on the comment the post is show correctly.

Thanks if you can help, I pass too much nights without sleep 🙁

(Sorry for mistakes, but usually I speak Italian 😉 )