Session variables not carrying to next page - php

Question

I've just begun using sessions and am having some headaches, I had this working last night, now opening it today...no longer works.
In my login processor I have the following if everything is OK. This script works fine, I have echoed the session variables to ensure that the array works, and it does.
$username - > post from login script
$encrypt_password -> created from password check further up the script
{
$session_name = 'LOGIN'; // Set a custom session name
$secure = false; // Set to true if using https.
$httponly = true; // This stops javascript being able to access the session id.
$cookie_lifetime = '3600';
$cookie_path = '/';
$cookie_domain = '127.0.0.1';
session_set_cookie_params($cookie_lifetime, $cookie_path, $cookie_domain, $secure, $httponly);
session_name($session_name); // Sets the session name to the one set above.
$group = $row['group_type'];
$user_browser = $_SERVER['HTTP_USER_AGENT']; /*grabs browser info*/
$user_id = preg_replace("/[^a-zA-Z0-9_\-]+/", "", $username); /*XSS Protection*/
$group_id = preg_replace("/[^a-zA-Z0-9_\-]+/", "", $group); /*XSS Protection*/
session_start();
$_SESSION['user']=$user_id;
$_SESSION['group_name']=$group_id;
$_SESSION['login_string'] = hash('sha512', $user_browser.$encrypt_password);
session_write_close();
header("location:".$group_id."_index.php");
}
I have created an include file which gathers the info from the session, included on every protected page, this is where it fell apart. I have created custom error codes for each if statement and have found that the if statement here fails. Echoing the session variables or evening printing the session array returns nothing.
$session_name = 'LOGIN'; // Set a custom session name
$secure = false; // Set to true if using https.
$httponly = true; // This stops javascript being able to access the session id.
$cookie_lifetime = '3600';
$cookie_path = '/';
$cookie_domain = '127.0.0.1';
session_set_cookie_params($cookie_lifetime, $cookie_path, $cookie_domain, $secure, $httponly);
session_name($session_name); // Sets the session name to the one set above.
session_start(); // Start the php session
session_regenerate_id(false); // regenerated the session, delete the old one.
if(isset($_SESSION['user'],$_SESSION['group_name'], $_SESSION['login_string']))
I was changing around the way the user groups worked before this broke, however none of the variables make it through. I am learning from his tut by the way: create a secure login script in php and mysql
Also do I need to call the session parameters every time a user visits a protected page?
Thanks in advance for any pointers.

Answer 1

Try putting session_start(); on TOP of everything, most importantly before you're calling a session. You're calling session_name($session_name); before it even started.
it=session

Answer 2

your regenerating the session on every page, which causes the previous session to destroy data.
remove session_regenerate_id(false);