此代码有什么问题。我总是会遇到这样的错误：

警告：无法修改标题信息-标题已由/home/krishnas/Documents/wordpress/wp admin/menu header.php:91）中的/home/krishnas/Documents/wordpress/wp includes/plugable发送。php在线866

$upload_dir = wp_upload_dir();
        $basedir = $upload_dir[\'basedir\'];
        $baseurl = $upload_dir[\'baseurl\'];
        $filename = "products_".date(\'YmdHis\').".xls";
        $fp = fopen($basedir.\'/\'.$filename,\'wr\');
        fwrite($fp,$content_final);
        $excell_file = $baseurl.\'/\'.$filename;
        //echo $basedir;
        //echo $baseurl;
        //exit;
        //exit;
        wp_redirect($excell_file);exit;}}?>