Problems with Auth

I have a Problem with the auth file: I works excellent on the first file. First the user come to the login screen and fills in the username and the password and the system confirms them. But then I have a link to another page. But on the other page a have no change to geht the information if he is logged in or not. I think i tried every possibility beside the right one. Do I have to register the variable $myauth to the session? It doesn't work either. On the next page the compiler tells me that i try to: Call to a member function on a non-object .... It is clear to me that he don't know the class, but how can I use the AUTH on more pages without logging in in every single page? Markus Scheffknecht File 1: <?php require_once "Auth/Auth.php"; session_start(); // set options $options = array( 'dsn' => 'mysql://test:test@localhost/test', 'table' => 'users', 'usernamecol' => 'username', 'passwordcol' => 'password' ); // define login form function function myloginform( $username ){ global $PHP_SELF; echo "<form method=\"post\" action=\"" . $PHP_SELF . "\"><br>"; echo "<input type=\"text\" name=\"username\"><br>"; echo "<input type=\"password\" name=\"password\"><br>"; echo "<input type=\"submit\">"; echo "</form>"; } // create auth object $myauth = new Auth( "DB", $options, 'myloginform', true); // start auth session $myauth->start(); if ($myauth->getAuth()) { echo "Welcome user ".$myauth->getUsername()."!<br />\n"; echo "<a href=\"test2.php\">Second page</a>"; } ?> File 2: <?PHP require_once "Auth/Auth.php"; session_start(); $myauth->setShowLogin("false"); // start auth session $myauth->start(); if ($myauth->getAuth ()) { echo "Welcome user to the 2nd page ".$myauth->getUsername()."! <br> "; echo "<a href=\"test2.php\">hallo</a>"; } else{ echo "Not logged in"; } ?>