it should be remebering both.
your code to set the username cookie, is setting the remember cookie:
<?php
if ((((isset($_POST["rememberme"]))?$_POST["rememberme"]:"") != "")) {
setcookie("remember", "".((isset($_POST["username"]))?$_POST["username"]:"") ."", time()+(60*60*24*30), "/", "", 0);
}?>
change it to:
<?php
if ((((isset($_POST["rememberme"]))?$_POST["rememberme"]:"") != "")) {
setcookie("username", "".((isset($_POST["username"]))?$_POST["username"]:"") ."", time()+(60*60*24*30), "/", "", 0);
}?>