将文件复制到新目录

Question

这就是我所拥有的，但我看不出有什么问题。

$site_name = $_SESSION['name'];

copy("../includes/teacher_webs_layout/index.php", "$site_name/index.php");
copy("../includes/teacher_webs_layout/teachers_web.php", "$site_name/teachers_web.php");
copy("../includes/teacher_webs_layout/teachers_web_sub.php", "$site_name/teachers_web_sub.php");
copy("../includes/teacher_webs_layout/.htaccess", "$site_name/.htaccess");

我正在尝试从teacher_webs_layout文件夹中取出它们并将它们复制到最近创建的$site_name文件夹中。