Vertical white line at low resolutions IE7

When viewing the theme in a small browser window or at low resolution in IE7 the background image appears to get shifted to the right, creating what looks like a vertical white line. See http://drupal-5x.themebot.org/?theme=dreamy for an example to try it on. I also attached an image to show you what it looks like. The problem is not too apparent at the default width of the theme but if you've made it wider, as I and others have, it becomes a pretty big problem at not all that low of a resolution.

I can get it to display correctly if I add "fixed" to the body background CSS, but when I do that the horizontal scrollbar shows up and when you scroll right the page scrolls while the background stays put so again you see the background. I prefer that problem but it's still a bit wacky to have your page do that.