PHP development: cookie-problem on the psp

Hi!
I don't really know if this is the right place to post but I've been having a problem viewing my website on the psp and I was hoping if someone could help me. The problem is creating a cookie in order to log in to my website. It works just fine on my computer, it creates a cookie and logs in, but when I try it on the psp it seems the cookie isn't created at all, even though I've typed the correct username and password. I'm using PHP's setcookie-function by the way.

Here's the code that's creating the cookie from my website:

<?php if ($_POST["username"] == "username" && $_POST["password"] == "pass") {
setcookie("usern", $_POST["username"], time()+3600);
}?>