Problem with the serialization XML (VB.Net, wpf application)

Hi,I have problem with my serialization. I have an object that contains a list of other objects. I need to serialize this object but always get an error. The principal Object is called "DataGeneraleAudit". The error is: 
"An error occurred during the reflection type"
 
Here is my object DataGeneraleAudit:

Imports System.Runtime.Serialization
Imports System.IO
Imports System.Xml.Serialization  <XmlRoot("DonneesLogiciel")> Public Class DataGeneraleAudit
    Public Sub New() 
    End Sub
#Region "Déclaration"
    Public _DataTotale As List(Of DataAudit)
#End Region 
#Region "Propiétés" <XmlAttribute("Total")> Public Property DonneeTotale() As List(Of DataAudit)
        Get
            Return _DataTotale
        End Get 
        Set(ByVal value As List(Of DataAudit))
            _DataTotale = value
        End Set
    End Property 
#End Region 

End Class
As you can see in the code, I create an object from a list of DataAudit. The Object DataAudit is compose for differents methodes and property and objects too.
 
Here is the Object "DataAudit":
Public Class DataAudit  

#Region "Declarations" 
    Private _Technologie As New DataTechnologie
    Private _Acquisition As New DataAcquisition
    Private _Resultats As New DataResultats 

#End Region
 
#Region "Propiétés" 
    Public Property Technologie() As DataTechnologie
        Get
            Return _Technologie
        End Get 
        Set(ByVal value As DataTechnologie)
            _Technologie = value
        End Set
    End Property 

    Public Property Acquisition() As DataAcquisition
        Get
            Return _Acquisition
        End Get
 
        Set(ByVal value As DataAcquisition)
            _Acquisition = value
        End Set
    End Property 
    Public Property ResultaAs As DataResultats
        Get
            Return _Resultats
        End Get 
        Set(ByVal value As DataResultats)
            _Resultats = value
        End Set
    End Property 
#End Region 
#Region "Méthodes" 

    Public Sub New()
   
    End Sub
 
#End Region 
End Class
and finally, here is the serialization:
Public Class MainWindow
    Public Sub New() 
        ' This call is required by the designer.
        InitializeComponent() 
        ' Add any initialization after the InitializeComponent() call.

    End Sub
 Friend nomFichierConfigXml As String
    Friend Config As New DataGeneraleAudit
 
 Private Sub MainWindow_Closing(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing 
        Try 
            ' Sérialization XML...
            Dim xSerializer As XmlSerializer = New XmlSerializer(GetType(DataGeneraleAudit))
            Dim writer As TextWriter = New StreamWriter("nomFichierConfigXml")
            xSerializer.Serialize(writer, Config)
            writer.Close() 
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try 
    End Sub
Where is the problem please? Somebody can help me?
Thank you
Langage: VB.NET, WPF Application