Cache miss

[Anon]

wonder if anyone can help me with this problem of session
i always get the msg Cache miss <http://xxxxx> ( url of my file ), what is causing the problem, the session id cannot be registered into my database and when logout, the session data was not deleted from my database either

the code below
store session data:
session_start();
session_register("username");
session_register("password");

				mysql_connect ($server, $user, $password1);
				mysql_select_db (FYP);
				mysql_query ("INSERT INTO session set session_id='$PHPSESSID', username='$username', password='$password'");
				mysql_close();

the code for logout( deleting the session data from database )
mysql_connect ($server, $user, $password1);
mysql_select_db (FYP);
mysql_query ("DELETE FROM session WHERE session_id='$PHPSESSID', username='$username', password='$password'");
mysql_close();

		session_unregister("username");
		session_unregister("password");
		session_destroy();

thanks