Thanks for looking, Paul. I've spent the entire day on this one problem, but the center column is still expanding about 30 pixels worth, underneath the right column for me if I set the IE6 font size setting to anything larger than "medium."
In my browser, it appears that the center column text itself is pretty much staying at the correct width, but I'm getting about 30 pixels of extra white padding to the right of that text, with the right border of the center column ending up about halfway across the right column, but underneath the right column.
I could hardly believe that I had found out what was causing the problem, but as soon as I did, I knew that it was going to work!
You know those translation links at the top of the center column? I finally realized that, in my IE6 browser, the text of those translation links was THE ONLY TEXT that was extending underneath the right column when I made the font larger. Because it was extending to the right, it was causing all the text below it (which stayed within its specified width) to have a lot more right padding.
That was the clue that told me to look at the code for those translation links, and that's how I finally "broke the case."
When, I replaced the non-breaking spaces between those translation links with regular spaces, the problem went away, and the page looked just like the screenshot that you did! Looking back at it, it shouldn't have taken me the whole day to figure that out.
Thanks for your help, Paul! The screenshot that you made was very helpful!