IE6 Issue (Block/Image Margin CSS?)

I have a slight problem with a block that displays an image (banner ad) at the top of my website (http://tinyurl.com/67y2ez4). The block displays correctly in all browsers except IE6 where the top section becomes too large. I have removed the block and confirmed that the issue goes away (i.e. it is definitely the block that is causing the problem). The theme is Acquia Marina which uses Fusion.

Can anyone help please?

Thank you.