DirectoryEntry and invoke problems - Help!

I am trying to call the backup method within IIS://LocalHost. This works easily via a VBS script but appears to be a real pain in VB.NET (console application). All this does is create a metabase backup on the host. Here is my code:

Code:

---

Dim MetaCon As New DirectoryEntry("IIS://LocalHost, "username", "password")

        Dim oParams As Object() = {"server", "MyBackups", "MD_BACKUP_NEXT_VERSION", "MD_BACKUP_SAVE_FIRST or MD_BACKUP_FORCE_BACKUP"}

        Try
            MetaCon.Invoke("backup", oParams)
        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try

---

Once it executes I get this error:

Exception has been thrown by the target of an invocation.

Any help would be GREATLY appreciated!