ok, i have been searching forever trying to find the wmi code that will successfully give me the directory sizes.  i found this code in ex A below, on this site.  It works.
The code in Sample B does not returns only nulls, but works otherwise.  example b code my have a few typos in it as i had made changes since i posted it.  but you'll get the drift.  i want to know why A works and B does not.  i'd pay 1000 points if i could to know this answer.

EXAMPLE A
============================================================================================
Public Shared Function GetDrives(ByVal RemotePc As String) As ArrayList
        Dim P As String = "\\" & RemotePc & "\root\cimv2:"
        Dim MyManagementClass As Management.ManagementClass = New Management.ManagementClass(P & "Win32_ComputerSystem")
        Dim MyManagementObjectCollection As System.Management.ManagementObjectCollection
        Dim MyDrives As New ArrayList
        Try
            MyManagementClass.Path.RelativePath = "Win32_LogicalDisk"
            MyManagementObjectCollection = MyManagementClass.GetInstances()
            For Each obj As Management.ManagementObject In MyManagementObjectCollection
                Dim MyDrive As New System.Text.StringBuilder
                MyDrive.Append(obj("Description"))
                MyDrive.Append(obj("Size"))
                MyDrives.Add(MyDrive.ToString)
            Next
        Catch e As Exception
        Finally
            If Not MyManagementObjectCollection Is Nothing Then
                MyManagementObjectCollection.Dispose()
            End If
            If Not MyManagementClass Is Nothing Then
                MyManagementClass.Dispose()
            End If
        End Try
        Return MyDrives
    End Function
====================================================

EXAMPLE B - not all the code is here, but a snippet that should show the logic
====================================================

       WMI related objects
        Dim ManScope As New Management.ManagementScope
        Dim ManScopePath As New Management.ManagementPath
        Dim ManOptions As New Management.ConnectionOptions
        Dim ManObject As New Management.ManagementObject
        Dim ManCollection As Management.ManagementObjectCollection
        Dim ManObjectSearcher As New Management.ManagementObjectSearcher
        '
        'SQL related objects
        Dim SQLCommand As New SqlClient.SqlCommand
        Dim SQLDataAdapter As New SqlClient.SqlDataAdapter
        Dim SQLMonitoredServersDataSet As New DataSet
        Dim SQLMonitoredServersDataSetRecord As DataRow

        'declaring parameters needed to save records
        Dim ServerIDPar As New SqlClient.SqlParameter
        '
        '----------------------------------------------------------------------------------------

        '----------------------------------------------------------------------------------------
        'Setting sql command properties
        '----------------------------------------------------------------------------------------
        SQLCommand.Connection = SQLConnection
        SQLCommand.CommandType = CommandType.StoredProcedure
        '----------------------------------------------------------------------------------------

        '----------------------------------------------------------------------------------------
        'Populating tables we will need for this procedure
        '----------------------------------------------------------------------------------------
        '
        SQLCommand.Parameters.Add(ServerIDPar)
        SQLCommand.Parameters.Add(ServerSizePar)

        ServerIDPar.ParameterName = "@ServerID"
        ServerSizePar.ParameterName = "@Size"
       
        ServerIDPar.Value = ServerID
       
         SQLCommand.CommandText = "MonitoredServices_Query"
        SQLDataAdapter.SelectCommand = SQLCommand
        SQLDataAdapter.Fill(SQLMonitoredServersDataSet)
        '----------------------------------------------------------------------------------------


        '----------------------------------------------------------------------------------------
        'Setup the WMI variables needed to collec the information we want to gather
        '----------------------------------------------------------------------------------------
        ManOptions.Authentication = AuthenticationLevel.Packet
        ManOptions.Impersonation = ImpersonationLevel.Impersonate
        '
        ManScopePath.Path = "\\" & ServerName & "\root\CIMV2"
        ManScope.Path = ManScopePath
        ManScope.Connect()
        '
        ManObjectSearcher.Scope = ManScope
        '
        If SQLMonitoredServersDataSet.Tables(0).Rows.Count <> 0 Then
            SubProgressBarIncrement = 100 / SQLMonitoredServersDataSet.Tables(0).Rows.Count
            For Each SQLMonitoredServersDataSetRecord In SQLMonitoredServersDataSet.Tables(0).Rows
                ManObjectSearcher.Query.QueryString = "Select * from Win32_Directory  where path = " & VBQuote & SQLMonitoredServersDataSetRecord.Item(0) & VBQuote  
                ManCollection = ManObjectSearcher.Get

                For Each ManObject In ManCollection
                   ServerIDPar.value = ServerID
                   ServiceSizePar.Value = ManObject.GetPropertyValue("Size")
                Next
                '
                SQLCommand.CommandText = "Win32_Server_Insert"
                SQLCommand.ExecuteNonQuery()
                Me.StatusBar.Panels("SubProgressBar").ProgressBarInfo.Value = Me.StatusBar.Panels("SubProgressBar").ProgressBarInfo.Value + SubProgressBarIncrement
                Me.StatusBar.Refresh()
            Next
        End If


        '----------------------------------------------------------------------------------------