Para mi que el problema viene de tu usuario y password.
Copia y pega éste código... (ya lo probé y me funciona perfecto)
Cita: Dim miOutlook As Outlook.Application = New Outlook.Application
Dim miNameSpace As Outlook._NameSpace = miOutlook.GetNamespace("MAPI")
miNameSpace.Logon("usuario", "password", Nothing, Nothing)
Dim oContactos As Outlook.MAPIFolder = miNameSpace.GetDefaultFolder(Outlook.OlDefaultFold ers.olFolderContacts)
Dim oItems As Outlook.Items = oContactos.Items
Dim oItem As Outlook.ContactItem = CType(oItems.GetFirst(), Outlook.ContactItem)
Label1.Text = oItem.FullName
Label2.Text = oItem.Email1Address
Label3.Text = oContactos.Items.Count.ToString()
miOutlook = Nothing
Espero que ahora si te funcione..
