banner erros

Well, I'm doing a website but I can get it validate in xhtml strict 1.0
because of the ad banner of the free service that I have to use.I can't fix
it because the free service doesn't allows me do that.It simply hide the
code fomr me , then I can't find it and so I can't fix it.Could you give me
some suggestion?
my website is: http://animewee.webng.com

Thanks!