This leads to an error

gistfile1.php

<?php
require_once '../include/conectar.php';


if (isset($_POST['borrar_id']) && is_array($_POST['borrar_id']))
{
    foreach ($_POST['borrar_id'] as $id)
    {
        $result_filename = $db->query("SELECT `direccion` FROM `imagenes` WHERE `id`='{$id}'");
        while ($result_filename->fetch_array())
        {
            unlink($result_filename);
            echo $result_filename;
        }
        $db->query("DELETE FROM `imagenes` WHERE `id`='{$id}'");
        //header ('Location: borrar.php');
    }
}
//header ('Location: borrar.php');

else
{
    //header ('Location: borrar.php');
}