ldap_connect returns LDAP link identifier on error
 The source:
// LDAP variables
$ldaphost = "nonexistendserver";  // your ldap servers
$ldapport = 389;                 // your ldap server's port number

// Connecting to LDAP
$ldapconn = ldap_connect( $ldaphost, $ldapport ) 
          or die( "Could not connect to {$ldaphost}" );
echo $ldapconn;

returns sth like this:

Resource id #11 

Any ideas???