The short answer is "i don't know".
The long answer is "I do not know".
Everything appears fine for me in both firefox and explorer, though I do 'design' for firefox. Some of the spacing can appear a bit off in explorer. Older explorer versions do not recognize some of the color coding for text so if you are seeing alot of gold text in the main posts, that's why... most text should be white or gray.
I suspect if you aren't using the most current version of either it may register some 'errors'. I've had other reports but have been unable to track down what it is or even really understand why it's happening. I doubt I'd be able to fix it even if I found the problem.
My best advice is to simply ignore it. I do... well, reports of it anyways
If you are seeing any visual problems with the site though, please let me know. If there is a codemonkey around, perhaps they might know a bit more.