MySQL - Fatal error: Class 'DB_Config' not found in C:\wamp\www\gg\includes\mysql.php on line 9

Hola a todos, la verdad no entiendo lo que pasa, soy nuevo en esto y tengo este error y necesito que me orienten porfa, este es el codigo que tengo y creo que es porque estoy unsando php5, este es mi codigo.

<?php


if (!defined('IN_SITE')){
die('Hacking attempt!');
}

class DBSql extends DB_Config
{
var $sverconn_id = 0;
var $dbconn_id = 0;

var $query_id = 0;
var $insert_id = 0;
var $record_row = array();
var $query_count = 0;

var $err_no = 0;
var $err_desc = "";

function DBSql(){
if ( !isset($this->db_host) || !isset($this->db_name) || !isset($this->db_username) || !isset($this->db_password) ){
$this->halt("Not found database information: database host, database name,...");
}
$this->connect();
$this->selectdb();
}

function connect(){
if ( empty($this->db_password) ){
if ($this->db_persistent){
$this->sverconn_id = @mysql_pconnect($this->db_host,$this->db_username) or $this->halt("Couldn't connect to database.");
}
else{
$this->sverconn_id = @mysql_connect($this->db_host,$this->db_username) or $this->halt("Couldn't connect to database.");
}
}
else{
if ($this->db_persistent){
$this->sverconn_id = @mysql_pconnect($this->db_host,$this->db_username,$this->db_password) or $this->halt("Couldn't connect to database.");
}
else{
$this->sverconn_id = @mysql_connect($this->db_host,$this->db_username,$this->db_password) or $this->halt("Couldn't connect to database.");
}
}
}

function selectdb($database=""){
if ( !empty($database) ) $this->db_name=$database;

$this->dbconn_id = @mysql_select_db($this->db_name,$this->sverconn_id) or $this->halt("Couldn't use this database:". $this->db_name);
if (!$this->dbconn_id){
$this->halt("Couldn't use this database: ".$this->database);
}
}

function query($query_string = "", $ann = 1){
if ( empty($query_string) ) $this->halt("Couldn't query an empty query string.");

if ($this->query_show){
echo "Query string: $query_string <br>";
$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$start_time = $mtime;
}

if ($this->err_show){
$this->query_id = mysql_query($query_string,$this->sverconn_id) or $this->halt("Couldn't query this query string: ". $query_string, $ann);
}
else{
$this->query_id = mysql_query($query_string,$this->sverconn_id) or $this->halt("Couldn't query a query string.", $ann);
}
$this->query_count++;

if ($this->query_show){
$mtime = microtime();
$mtime = explode(" ",$mtime);
$mtime = $mtime[1] + $mtime[0];
$end_time = $mtime;
$totaltime = ($end_time - $start_time);
echo "Time query: $totaltime<br>";
}

return $this->query_id;
}

function fetch_array($query_id=-1){
if ( $query_id!=-1 ) $this->query_id=$query_id;
if ( !$this->query_id ) $this->halt("Invalid query id");

$this->record_row = mysql_fetch_array($this->query_id, MYSQL_ASSOC);

return $this->record_row;
}

function fetch_all_array($query_id=-1){
if ( $query_id!=-1 ) $this->query_id=$query_id;
if ( !$this->query_id ) $this->halt("Invalid query id");

$record = array();
while ( $tmp_info = mysql_fetch_array($this->query_id, MYSQL_ASSOC) ){
$record[] = $tmp_info;
}

return $record;
}

function fetch_row($query_id=-1){
if ( $query_id!=-1 ) $this->query_id=$query_id;
if ( !$this->query_id ) $this->halt("Invalid query id");

$this->record_row = mysql_fetch_row($this->query_id);

return $this->record_row;
}

function num_rows($query_id=-1){
if ( $query_id!=-1 ) $this->query_id=$query_id;
if ( !$this->query_id ) $this->halt("Invalid query id");

return mysql_num_rows($this->query_id);
}

function num_fields($query_id=-1){
if ( $query_id!=-1 ) $this->query_id=$query_id;
if ( !$this->query_id ) $this->halt("Invalid query id");

return mysql_num_fields($this->query_id);
}

function field_name($query_id,$field_id){
return mysql_field_name($query_id,$field_id);
}

function list_tables($dbname=""){
if (!empty($dbname)){
$this->db_name = $dbname;
}

$this->query_id = mysql_list_tables($this->db_name);
return $this->query_id;
}

function get_serverinfo(){
return mysql_get_server_info();
}

function data_seek($row_number=0){
return mysql_data_seek($this->sverconn_id, $row_number);
}

function insert_id(){
$this->insert_id = mysql_insert_id();
return $this->insert_id;
}

function get_query_count(){
return $this->query_count;
}

function free_result($query_id=-1){
if ($query_id!=-1) $this->query_id = $query_id;
return @mysql_free_result($this->query_id);
}

function drop_db($dbname=""){
if ( empty($dbname) ) $this->halt("Dropt DB: Invalid db name");
return mysql_drop_db($dbname,$this->sverconn_id);
}

function fetch_field($query_id=-1){
if ($query_id!=-1) $this->query_id = $query_id;
return mysql_fetch_field($this->query_id);
}

function close(){
return @mysql_close($this->sverconn_id);
}

function halt($msg, $ann=1){
if ($ann == 0) return;

$this->err_no = mysql_errno();
$this->err_desc = mysql_error();

echo "<br><br><center><b>ERROR</b></center><br>";
echo $msg;
echo "<br>Please contact admin about this err. <a href='javascript:history.back(-1);'>Back</a>";

if ($this->err_show){
echo "<br><br><b>DETAIL</b><br>";
echo $this->err_no," : ",$this->err_desc;
}

if ( ($this->err_report) && !empty($this->technical_email) ){
$subject = "Database error in ". getenv("HTTP_HOST");
$message = "Database error in ". getenv("HTTP_HOST");
$message .= "\n\n<b>$msg</b>\n";
$message .= "\nError Number: ". $this->err_id;
$message .= "\nError Detail: ". $this->err_detail;
$message .= "\nDate: ". date("l dS of F Y h:i:s A");
$message .= "\nScript File: [url]http://"[/url];. getenv("HTTP_HOST") . getenv("SCRIPT_NAME");
@mail($this->technical_email,$subject,$message,"From: $this->technical_email") or die("SMTP ERROR. Could not send email.");
}

$this->close($this->sverconn_id);
die();
}
}

?>

Dicho en cordobés básico: Esto no tiene un pomo que ver con MySQL. Esto es PHP.

Te doy una ayuda: Estás declarando una clase que extiende a otra, pero no estás definiendo previamente la clase que pretendés extender.
O sea: Te falta aprender programación en PHP Orientada a Objetos.