Suggestion: If you rebuild the site, have the main content page end with the bottom of the left and right columns, if possible. Right now the main content is seen well below the right and left columns. I think it would look killer after that! Good job!
I just hésitate a little, because the background of carbonation isn't white, it will be a little strange with the pictures.
I will try some modifications, to see that...
And yes, I will try to reach the bottom with the main, for sure it will be cleaner.
Great job, the forum is perfectly integrated, navigation easy, a lot of useful informations.
Little things: in TESTS ET DOSSIERS, these two images are not loaded: web_links.jpg and tuto_oc_amd64.jpg.
And your hover on main tabs (in Menu 1) is dark grey and not very easy to read on dark blue background.