Hi Inca,
Simply as a means of comparison, this is what I receive when I render the same page under my Opera 11:

I notice that you have a lot of the text as in italics. Could you tell me if your computer has any text magnification or alterations enabled, either in windows or in the browser itself?
Could you try to disable these and see if it fixes the problem? This is not a requirement of the site but I think I have found the problem and will fix it, but in the mean time it may enable you to read the forums.
Similarly, can you try Ctrl+Scroll (This zooms in and out) to see if that will fix it.
Also, i'm assuming this bug is on all pages? (Or is it just on those with the menu at the top?)
Thanks,
J250