Help needed regarding my Project

Public Class AppSettings
   Private _configFileName As String 'local var to hold the config file name
   Private _configFileType As Config 'local var to hold the config file type (private or shared)

   'config file options
   Public Enum Config
      SharedFile  'all users use the same config file
      PrivateFile 'each user has their own config file
   End Enum
 
   'constructor
   Public Sub New(ByVal ConfigFileType As Config)
      _configFileType = ConfigFileType 'remember this setting

      InitializeConfigFile() 'setup the filename and location
   End Sub
 
   'initialize the apps config file, create it if it doesn't exist
   Private Sub InitializeConfigFile()
      Dim sb As New Text.StringBuilder
 
      'build the path\filename depending on the location of the config file
      Select Case _configFileType
         Case Config.PrivateFile 'each user has their own personal settings
            'use "\documents and settings\username\application data" for the config file directory
            sb.Append(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData))
         Case Config.SharedFile 'all users share the same settings
            'use "\documents and settings\All Users\application data" for the config file directory
            sb.Append(Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData))
      End Select
 
      'add the product name
      sb.Append("\")
      sb.Append(Application.ProductName)
 
      'create the directory if it isn't there
      If Not IO.Directory.Exists(sb.ToString) Then
         IO.Directory.CreateDirectory(sb.ToString)
      End If
 
      'finish building the file name
      sb.Append("\")
      sb.Append(Application.ProductName)
      sb.Append(".config")
 
      _configFileName = sb.ToString 'completed config filename

      'if the file doesn't exist, create a blank xml
      If Not IO.File.Exists(_configFileName) Then
         Dim fn As New IO.StreamWriter(IO.File.Open(_configFileName, IO.FileMode.Create))
         fn.WriteLine("")
         fn.WriteLine("<configuration>")
         fn.WriteLine("  <appsettings>")
         fn.WriteLine("    <!--   User application and configured property settings go here.-->")
         fn.WriteLine("    <!--   Example: <add key=""settingName"" value=""settingValue""/> -->")
         fn.WriteLine("  </appsettings>")
         fn.WriteLine("</configuration>")
         fn.Close() 'all done
      End If
   End Sub
 
   'get an application setting by key value
   Public Function GetSetting(ByVal key As String) As String
      'xml document object
      Dim xd As New Xml.XmlDocument
 
      'load the xml file
      xd.Load(_configFileName)
 
      'query for a value
      Dim Node As Xml.XmlNode = xd.DocumentElement.SelectSingleNode( _
                                "/configuration/appSettings/add[@key=""" & key & """]")
 
      'return the value or nothing if it doesn't exist
      If Not Node Is Nothing Then
         Return Node.Attributes.GetNamedItem("value").Value
      Else
         Return Nothing
      End If
   End Function
 
   'save an application setting, takes a key and a value
   Public Sub SaveSetting(ByVal key As String, ByVal value As String)
      'xml document object
      Dim xd As New Xml.XmlDocument
 
      'load the xml file
      xd.Load(_configFileName)
 
      'get the value
      Dim Node As Xml.XmlElement = CType(xd.DocumentElement.SelectSingleNode( _
                                         "/configuration/appSettings/add[@key=""" & _
                                         key & """]"), Xml.XmlElement)
      If Not Node Is Nothing Then
         'key found, set the value
         Node.Attributes.GetNamedItem("value").Value = value
      Else
         'key not found, create it
         Node = xd.CreateElement("add")
         Node.SetAttribute("key", key)
         Node.SetAttribute("value", value)
 
         'look for the appsettings node
         Dim Root As Xml.XmlNode = xd.DocumentElement.SelectSingleNode("/configuration/appSettings")
 
         'add the new child node (this key)
         If Not Root Is Nothing Then
            Root.AppendChild(Node)
         Else
            Try
               'appsettings node didn't exist, add it before adding the new child
               Root = xd.DocumentElement.SelectSingleNode("/configuration")
               Root.AppendChild(xd.CreateElement("appSettings"))
               Root = xd.DocumentElement.SelectSingleNode("/configuration/appSettings")
               Root.AppendChild(Node)
            Catch ex As Exception
               'failed adding node, throw an error
               Throw New Exception("Could not set value", ex)
            End Try
         End If
      End If
 
      'finally, save the new version of the config file
      xd.Save(_configFileName)
   End Sub
End Class