Have you fixed this? It looks correct in my browsers. A few things to consider though, if your still seeing issues on other pc's then it's most likely due to the version of IE that's being used and how it's interacting with the rest of the site.
I'm running my IE9 browser in compatibilty mode which fixes alot of issues but on the older versions of IE which are considered non-modern browsers (IE7 and IE8) I have seen a lot of inconsistancies with how it renders a page. I really don't have an answer for you as far as the code is concerned because it appears to be working, the only thing that jumps out at me is the fixed position.
IE7 and IE8 support the fixed value only if a !DOCTYPE is specified.