that doens't sound like a css issue, but a dynamic object model issue. I'm not really sure how to debug that in IE6 directly. these kinds of issues are why I've completely abandoned ie6.
if you're actually using ie8 but embded in a vb6 app so that it emulates ie6 by default, you can change that and relive a lot of headaches.
http://stackoverflow.com/questions/6717055/how-do-i-turn-off-compatibility-view-on-the-ie-webbrowsercontrol-in-a-winforms-a