ie6 will push content down the page like that if the content is wider than the box it is in.
You will need to modify the width of items in the left content section so that it can fit in the available box.
Start by removing all the content and slowly adding it back in a paragraph at a time till you find the problem element, then modify that elements width down by 10px at a time to find a width that will work, you can then increase the width 1px at a time till you find the max width IE 6 will allow.
