Problem LDAP and Win2003 AD

[User79]

Hello!
I'm trying simple scripts to browse an Active Directory via LDAP
functions...
My domain is: schoollm.lan

The script I'm trying:

----------
$root_dn = "ad***********@mascheroni.lan";
$root_pw = "secret";

$conn = ldap_connect("192.168.10.1") or die("Could not connect to
server");

ldap_set_option($conn, LDAP_OPT_PROTOCOL_VERSION, 3);

$r = ldap_bind($conn, $root_dn, $root_pw) or die("Could not bind to
server");

$result = ldap_search($conn,"dc=schoollm, dc=lan","(cn=*)") or die
("Error in search query");

$info = ldap_get_entries($conn, $result);

for ($i=0; $i<$info["count"]; $i++)
{
echo "dn is: ". $info[$i]["dn"] ."<br>";
echo "first cn is: ". $info[$i]["cn"][0] ."<br>";
echo "first email address is: ". $info[$i]["mail"][0] ."<p>"; }

echo "Number of entries found: " . ldap_count_entries($conn, $result)

ldap_close($conn);
----------

I always get this error:

Warning: ldap_search(): Search: Operations error in
C:\Programmi\Apache Group\Apache2\htdocs\ldap.php on line 12
Error in search query

Where I'm wrong?
THANKS!