Cookie and function prob.

I am trying this thingy here..
I need to check a users cookie vars to check if the user has acces to this site.

If he does not have access, I send the user to the logon page...

But this script only redirects the user to the logon page whatever I do!!!

But, if I define the "checkaccess" variables in the top of the script, it works!

I am setting the vars in a differnet script. I know they are set, because I can echo them out.....

Is there something here I`ve missed... or am I not making any sense?

<?
if (!checkaccess($cook_ab_nr, $cook_password)) {
header("location:http://www.havneavisen.net/abonnent/logg.php?artikelid=747") ;
exit ;
} else {
?>

<body>

<?
echo "NAH NAH NAH NAH" ;
?>

</body>

<?
} // end check access
?>