add users in microsoft active directory via php ldap_add
===

I have tried adding users via php ldap active directory for Microsft 2008 r2 datacenter, but I can not get this error: 

An error occurred. Error number 64: Naming violation
The code is:

    <?php 
    $ldaprdn = 'administrador@correo.mx'; 
    $ldappass = 'dir378prob@'; 
    $ds = 'correo.mx'; 
    $dn = 'ou=usuarios,dc=correo,dc=mx'; 
    $puertoldap = 389; 
    $ldapconn = ldap_connect($ds,$puertoldap)or die("ERROR: I Don'n connect to LDAP."); 
		 
    if ($ldapconn) 
    { 
    ldap_set_option($ldapconn, LDAP_OPT_PROTOCOL_VERSION,3); 
    ldap_set_option($ldapconn, LDAP_OPT_REFERRALS,0); 
    $con = ldap_bind($ldapconn, $ldaprdn, $ldappass); 
    if ($con) 
    { 				

    $info["cn"] = $_POST['cn'];
    $info["sn"] = $_POST['sn'];
    $info["mail"] = $_POST['mail'];
    $info["objectclass"] = "inetorgperson";

    // prepare DN for new entry
    $dn_aux = "mail=" . $_POST['mail'] . ",ou=usuarios,dc=correo,dc=mx";
    $result = ldap_add($ldapconn, $dn_aux, $info);

    if($result) 
    {
    echo "New entry with DN " . $dn . " added to LDAP directory."; } 
    // else display error   
    else 
    {
    echo "An error occurred. Error number " . ldap_errno($conn) . ": " .
    ldap_err2str(ldap_errno($conn)); }

    } 
    else 
    { 
    echo "Error en LDAP bind..."; 
    } 
    } 
    ldap_close($ldapconn); 
    ?> 


can anyone help?

I'm taking my first steps in this ldap, so please could explain in detail, thanks

Saludos desde mexico . . .