Add code to Vantage theme

Hey,
I have signed up for Aweber to add a newsletter form to my website. As part of the installation I need to add the following code to my site:

(function(d, s, id) {
var js, fjs = d.getElementsByTagName(s)[0];
if (d.getElementById(id)) return;
js = d.createElement(s); js.id = id;
js.src = “//forms.aweber.com/form/83/1926195111.js”;
fjs.parentNode.insertBefore(js, fjs);
}(document, “script”, “aweber-wjs-59oiivt7a”));

I should add the code somewhere between the body-tags. I have done the same thing on other themes, and then it has worked. But in the Vantage theme, nothing happens. I have created a child theme, but I have tried both adding the code to the parent theme and create a new file and added that to the childtheme.
The file I have altered is header.php. This has been the file in other themes. Any suggestions on how to proceed?
Thanks in advance!
// Anders

URL: http://casinofakturan.se