PHP Code Login Failure [on hold]

I'm kinda new at working with PHP. I'm trying to make a system with a Login, a friend helped me with the codes, but an error appears when I'm trying to connect to the data base.

I'm using: * Wampserver * PostgreSQL

After logging in, I get this error:

Fatal error: Call to undefined method DBConnection::Consultar() in C:\wamp\www\Intranet\App\Controllers\validaringreso.php on line 11

And in the php code I have this:

1  <!-- validaringreso.php -->
2  <?php
3  //@session_start();
4  include($_SERVER['DOCUMENT_ROOT'] . "Intranet/App/Models/funciones.php");
5  include($_SERVER['DOCUMENT_ROOT'] . "Intranet/App/Models/conect_.php");
6  
7  $login=addslashes($_POST["usuario_emp"]);
8  $pass=addslashes($_POST["contrasena_emp"]);
9  $bd=new DBconnection();
10 $bd->sentencia="SELECT * FROM usuarios_emp WHERE usuario_emp='$login' AND contrasena_emp='$pass'";
11 $rs=$bd->Consultar();
12 if($bd->NumeroFilas($rs)>0){
13  $fila=$bd->AvanzarFila($rs);
14  $_SESSION["id"]=$fila["id"];
15  $_SESSION["usuario_emp"]=$fila["usuario_emp"];
16  $_SESSION["constrasena_emp"]=$fila["constrasena_emp"];
17  $bd->LiberarResultado($rs);
18  $bd->Cerrar();
19  header('Location: principal.php');
20 }else{
21  echo "<script language='javascript'>
22 alert('Datos Incorrectos');
23 parent.location.href = 'index.php';
24 </script>";
25 }
26 ?>