DBConnection error and include_once error

Now i hope this topic stays here,

Im trying to install a webpage on my own server, im working on a windows 2019 server with IIS and PHP 7.1

I have installed The zend loader 7.1 with no errors, the page need that one to work.

My structure on the page is :

wwwroot: index.php, common.php
wwwroot/assets/libraries: defines.php, class.dbquery.php

But when i open the page on localhost i only see errors.

My errors:

Fatal error:  Uncaught Error: Class 'DBConnection' not found in \assets\libraries\defines.php:37
Stack trace:
#0 \common.php(15): require_once()
#1 \index.php(2): include_once('C:\\inetpub\\wwwr...')
#2 {main}
  thrown in \assets\libraries\defines.php on line 37

In \assets\libraries\defines.php line 37 is the DBConnection that gives fatal error.

if($_SERVER["HTTP_HOST"] == "localhost")
    {
        define( 'TSITE_SERVER','localhost');
        define( 'TSITE_DB','xxxxx');
        define( 'TSITE_USERNAME','root');
        define( 'TSITE_PASS','xxxxx');
    }
define('PAYPAL_CLIENT_ID', ''); // Paypal client id
define('PAYPAL_SECRET', ''); // Paypal secret

if(!isset($obj))
{
    require_once(TPATH_CLASS."class.dbquery.php");
    $obj=   new DBConnection(TSITE_SERVER, TSITE_DB, TSITE_USERNAME,TSITE_PASS);
}

in common.php it´s require_once a php script that i have in the assets/libraries folder.

require_once TPATH_BASE . DS . "assets" . DS . "libraries" . DS . "defines.php";

and from index.php it´s include_once common.php that is in the same folder as index.php.

<?php
  include_once("common.php");

I have search on the internet based on the error, but i cant find anything, This kind of code is new for me. And i can´t remove the errors.