I try to Setcookie to write in client browser with this script

<? 
	if(!$CartID){
	$CartID=md5(uniqid(rand()));
	SetCookie("CartID",$CartID,time()+3600);
	}
?>

It's work well with Redhat with Apache but When I try to user this script in Win2k with IIS5.0 It doesn't work.
No cookie was write.
detail in PHP.in  as following:

session.auto_start Off 
session.cache_expire180 
session.cache_limiter nocache 
session.cookie_domain no value 
session.cookie_lifetime 0 
session.cookie_path / 
session.cookie_secure Off 
session.entropy_file no value 
session.entropy_length 0 
session.gc_maxlifetime 1440 
session.gc_probability 1 
session.name PHPSESSID 
session.referer_check no value 
session.save_handler files 
session.save_path /tmp 
session.serialize_handler php 
session.use_cookie On 

Thank you