Google adsense rejection

Hi,
I'm trying to make adsense work on my second blog, named skole365.dk, but I keep getting rejected.

I have asked in a google group and was told that my server issues the wrong header, what ever that means.

Do you know have to solve the problem, and make my site available to google's bots.

Thanks,

Peter

Ps: This is the top of the header:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" dir="ltr" lang="da-DK">
<head profile="http://gmpg.org/xfn/11">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />