无法通过邮件php网站设置+读取cookie

Question

I have a simple mail script. It send me the contents of a php website (my own website) via file_get_contents('http://www.xxxx.com/xxxx.php');

That works perfect. The only problem is: when I visit that website, it puts data in a cookie. Next time I visit that website, it displays data out of that cookie and puts new data in that cookie. Works perfect. But when I call the url via file_get_contents('http://www.xxxx.com/xxxx.php') to send the website to my email, the cookie data cannot be set and not be read from the cookie. Can somebody explain that?

Thanks a lot!