creating a module in prestashop: error 'class Module cannot be found'

Question

i have a presta module in php4. It works by connecting to the database of a prestashop and prints out xml. Whiles trying to upload to their apps store, they asked i make it php5 and follow certain proceedures.

• In a nutshell, its just a full structural code with 1 method that gets connection to a prestashop database and prints out xml.

So the problem is how to get it to conform to the php5 standard required by prestashop. When i tried, i get this error. "class Module cannot be found"

<?php
include('config/settings.inc.php');
$con = mysql_connect(_DB_SERVER_, _DB_USER_, _DB_PASSWD_);
mysql_select_db(_DB_NAME_);
$str = '_DB_PREFIX_';
$str1 = constant($str);
$sql = 'SELECT '.
$str1.'product_lang.name,'.
$str1.'product.id_product as id,'.
$str1.'product.quantity,'.
$str1.'product.price,'.
$str1.'product.weight,'.
$str1.'product_lang.description,'.
$str1.'product_lang.link_rewrite as url,'.
$str1.'category_lang.name as category,'.
$str1.'manufacturer.name as manufacturer,'.
$str1.'image.id_image '.

'FROM '.
$str1.'product_lang '.
'INNER JOIN ' .$str1.'product '.
'ON ('.$str1.'product_lang.id_product = '.$str1.'product.id_product) '.
'INNER JOIN ' .$str1.'image '.
'ON ('.$str1.'image.id_product = '.$str1.'product.id_product) '.
'INNER JOIN ' .$str1.'manufacturer '.
'ON ('.$str1.'manufacturer.id_manufacturer = '.$str1.'product.id_manufacturer) '.
'INNER JOIN ' .$str1.'category_lang '.
'ON ('.$str1.'category_lang.id_category = '.$str1.'product.id_category_default) '.
//'WHERE '.$str1.'product_lang.id_lang = 1 AND '.$str1.'category_lang.id_lang = 1';
    'WHERE '.$str1.'product_lang.id_lang = 1';
    $result = mysql_query($sql);

     header("Content-Type: text/xml; charset=ISO-8859-1");
     $output = '<?xml version="1.0" encoding="utf-8"?>
     <products>';
     while($row = mysql_fetch_assoc($result)):
     //echo "<br><br><b>text:</b>".$text = addslashes($text);
     $text = str_replace(chr(145), "\'", $text);
 $output .= '
<product>
    <id>'. $row['id'].'</id>
    <name><![CDATA['.$name.']]></name>
    <description><![CDATA['.$text.']]></description>
            <image><![CDATA['. 'http://'.$_SERVER['HTTP_HOST'].__PS_BASE_URI__.'img/p/'.$row['id'].'-'.$row['id_image'].'.jpg' .']]></image>
        <quantity><![CDATA['. $row['quantity'] .']]></quantity> 
        <price><![CDATA['. $row['price'] .']]></price>
        <weight>'. $row['weight'] .'</weight>
    <category><![CDATA['.$category.']]></category>
    <manufacturer><![CDATA['. $manufacturer.']]></manufacturer>
            <url><![CDATA['.'http://'.$_SERVER['HTTP_HOST'].'/product.php?id_product='.$row['id'].']]></url>

     </product>';
 endwhile;

 print $output .= '
 </products>';

This is the proceedure of coding i need to follow from prestashop

<?php
       //Your class must have the same name than this file.

      class module_name extends Module
       {
      public function __construct()
       {

    //Name of your module. It must have the same name than the class
    $this->name = 'module_name';

    //You must choose an existing tab amongst the ones that are available
    $this->tab = 'You choose';

    //The version of your module. Do not forget to increment the version for each modification
    $this->version = '1.0';

    //The constructor must be called after the name has been set, but before you try to use any functions like $this->l()
    parent::__construct();

    //Name displayed in the module list
    $this->displayName = $this->l('Display Name on Back Office');

    //Short description displayed in the module list
    $this->description = $this->l('Description On Back Office');    
}

//You must implement the following methods if your module need to create a table, add configuration variables, or hook itself somewhere.
//-------------------------------
public function install()
{
    return parent::install();
}

public function uninstall()
{
    return parent::install();
}
//-------------------------------

//Display Configuration page of your module.
public function getContent()
{
    return 'Hello World!';
}

   }

 ?>