Error in extending class to connect to mysql

Hello,
I am having trouble with my script. I get this error:

"Warning: mysql_select_db(): supplied argument is not a valid MySQL-Link resource in /home/imperia/public_html/testaccess.php on line 7
Could not select database because" (<---- That is a custom error message in my file)

I am trying to create management system from the ground up and right now I am at the part where I get the pages from a database. This is my first time using classes in php but after I read a certain chapter in my C++ book I understood some things like the "->" and "$this" operator better but I don't know where to put them still. Any help on solving the select db problem? Thanks!
----------begin queries.php-------------
<?php
require('settings.php');
class DBconnector {
      var $name = "DBconnector";
      function DbConnect($host, $user, $pass){
            mysql_connect($host, $user, $pass) or die($error001." ".mysql_error());
            }
      }
class QueryDB {
      var $name = "QueryDB";
      function GetPage($id){
      $Pageget = "select id, content from mainpage where id = ${id}";
      $PageGetRes = mysql_query($PageGet);
            while($DisplayPageGet = mysql_fetch_array($PageGetRes)) {
            $content = stripslashes($DisplayPageGet['content']);
                  }
      }
}
?>
---------------------End queries.php-----------------------------
----------begin testpage.php-----------
<?PHP
require('include/queries.php');
class page extends DBconnector{
      var $conn;
      function SelectDB($db, $host, $user, $pass){
      $conn = $this->dbconnect($host,$user, $pass);
      mysql_select_db($db, "$conn");
      }
}
$page = new page;
$page->SelectDB("$mysql[db]","$mysql[host]","$mysql[uname]","$mysql[pass]") or die($error002." ".mysql_error());

?>
-------------end testpage.php------------      Start Free Trial