Ok... me faltó una linea...
Ahora el error me lo marca EL MISMO ERROR en la linea siguiente...
Código:
Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpdate.Click
'Try
'Send updates to xml file
Dim xDoc As XmlDocument = New XmlDocument()
xDoc.Load("Contactos.xml") '<----- LA LINEA QUE FALTABA
Dim root, id As XmlNode
Dim i As Integer
root = xDoc.DocumentElement
For i = 0 To root.ChildNodes.Count - 1
id = root.ChildNodes(i).Attributes("CustomerID")
If (id.InnerText = txtUniqueID.Text) Then 'AHORA AQUI ME SEÑALA EL ERROR
xDoc.DocumentElement("CustomerID").Value = txtUniqueID.Text
xDoc.DocumentElement("CompanyName").Value = txtCoName.Text
xDoc.DocumentElement("ContactName").Value = txtContact.Text
xDoc.DocumentElement("ContactTitle").Value = txtTitle.Text
xDoc.DocumentElement("Address1").Value = txtAddress.Text
xDoc.DocumentElement("Phone1").Value = txtPhone1.Text
xDoc.DocumentElement("Phone2").Value = txtPhone2.Text
End If
Next i
xDoc.Save(m_connCustomers)
'Reset and begin again
LoadDataSet()
MsgBox("Record has been updated.")
'Attempt to update the datasource.
Me.LoadDataSet()
'Catch eUpdate As System.Exception
' 'Add your error handling code here.
' 'Display error message, if any.
' System.Windows.Forms.MessageBox.Show(eUpdate.Message)
'End Try
Me.dsCust_PositionChanged()
End Sub