Not sure what's causing the problem with it, it looks like you are only running the IIP on your index page at the present time. Double-check your header and footer for now to make sure they are compliant, that way you'll have an easier time of it come upgrade. It might clear up a lot of your current problems as well.
Make a dummy html page and copy/paste your headerinsert/header/footer into it and run it through the validator.
