Session Variables

I have a quirky problem that should be a breeze for someone who is smarter than I. I have a script where I am registering a HTML form post variable as a session variable and then echo it. In the real script I use it in a MySQL query, but for the sake of this post, here is the "script": $user1 = $HTTP_POST_VARS["user1"]; session_register("user1"); echo $HTTP_SESSION_VARS["user1"]; This doesn't work, however, if I hit the refresh button the var miraculously appears! What am I doing wrong?