Authentication in ADSI

Hi,
I am trying to authenticate users and passwords
our test Domain is MHCB.COM.AU

My test user login is "markadmin"
Password of "password"
Organisational Unit of "testibj"
Full Name is "mark b"

I receive the following after using the following code of
Automation error
Logon failure: unknown user name or bad password.

strPassword = "password"

'Have tried both of the following neither of which is successful

struserUPN = "CN=mark b,CN=testIBJ ,DC=mhcb ,DC=com ,DC=au"
struserUPN = "CN=mark b ,DC=mhcb ,DC=com ,DC=au"

Set objDsOpenObject = GetObject("LDAP:")
Set objDomain = objDsOpenObject.OpenDSObject("LDAP://" &
strUserUPN, strUserUPN, strPassword,
ADS_SECURE_AUTHENTICATION)

But I don't know why and although all accounts are set to
lock after 3 bad password attempts this account does not
get locked out no matter how many times I get the
error !!!!

However when I try the following it works

Set objDsOpenObject = GetObject("WinNT:")
Set objDomain = objDsOpenObject.OpenDSObject
("WinNT://MHCB.COM.AU", "markadmin", strPassword,
ADS_SECURE_AUTHENTICATION)

Could someone explain what I am doing wrong with my LDAP
version of authentication

Thanks in Advance !!!!
[1367 byte] By [sniper_boy] at [2007-11-17 14:29:38]