I noticed this was a fluid design. You have the content floating left and the right side floating right....I noticed when I hit the square icon in Firefox (not the minimize button but the one that looks like a box next to the exit button - I just realized I don't know what it's called! LOL) it slides into place and the far right scroll bar disappears.
Firefox and IE have a slight difference with that far right scroll bar padding. If the design doesn't have to be fluid, you can set the wrapper to be a certain width and subtract 200 from that to come up with a fixed content width.
Otherwise, you can change the width of #right to about or less than 195px.