I did found an answer, have you ever heard about P3P? It is basically a securtiy measure that only IE uses these days and that conflicts directly with implementing Iframes that have sources from two different servers (ex. your website and qlikview).
So, to fix this you need to go to the web.config of your QvAjaxZfc project and implement something like this:
<add name="P3P" value='CP="This is a mock P3P policy."' />
Pages like Google and Facebook use these kind of mock P3P policies to be able to display Iframes and other things without problems. One thing, you should probably link to a page that has more info about why you don't have those policies implemented and your privacy policies.
More info on P3P: http://msdn.microsoft.com/en-us/library/ie/ms537341(v=vs.85).aspx
Hope this helps.