All'esecuzione di questo codice:
<?php
$query="select * from VENDITORE where NickV='".$_POST['Usr']."' and PasswordV='".$_POST['Psw']."'";

$path='C:/WWW/DatabaseAccess/';

$db_name='AsteOnLine.accdb';
$dsource=$path.$db_name;

$cn_string='Provider=Microsoft.ACE.OLEDB.12.0;';
$cn_string.="Data Source=$dsource;";

if (!file_exists($dsource)){
die("Il database non esiste");
}

$cn=new COM("ADODB.Connection");
$cn->open($cn_string);

$rs=new COM("ADODB.Recordset");
$rs->Open($query,$cn);

if (!$rs->EOF) {echo "Nome utente e/o password errati";}
else{

$rs->Close();
$rs=null;

$query="select max(Cod)+1 as COD from ARTICOLO";
$rs=new COM("ADODB.Recordset");
$rs->Open($query,$cn);

$query="insert into ARTICOLO values('".$rs->Fields['COD']->value."','".$_POST['prz']."',DateAdd(\"d\",'".$_POST['DF']."',Date()),'".$_POST['Dscrz']."')";
$kk=new COM("ADODB.Recordset");
$kk->Open($query,$cn);

echo "Nuovo articolo messo all'asta!!!";

$rs->Close();
$rs=null;
$kk->Close();
$kk=null;

$cn->Close();
$cn=null;}
?>

mi viene segnalato questo errore:
Fatal error: Uncaught exception 'com_exception' with message 'Source: Microsoft Office Access Database Engine
Description: Nessun valore specificato per alcuni parametri necessari.' in C:\WWW\New.php:20 Stack trace: #0 C:\WWW\New.php(20): com->Open('select * from V...', Object(com)) #1 {main} thrown in C:\WWW\New.php on line 20

Che è successo?