Ini-File reader with kernel32.dll do not read from file - vb.net

Question

I have the Problem that my script writes only the default value to the new Ini-File. It sould read the value from the BackupConfig. I do not see my error, yet. The output of the MessageBox should be the old URL but it prints google.
I hope you can help me, thank you.
My script looks like this
My.Computer.FileSystem.MoveFile(ConfigName, "backup.Config.ini", True)
Thread.Sleep(2000)
Dim Config As IniFile = New IniFile(ConfigName)
Dim BackupConfig As IniFile = New IniFile("backup.Config.ini")
MessageBox.Show(BackupConfig.GetString("Window08", "Url", "http://google.de"))
Config.WriteInteger("Setup", "Opacity", BackupConfig.GetInteger("Setup", "Opacity", 100))
This is my IniFile Class, i found it here on Stackoverflow an do not know which user posted it. (Sorry for that)
Public Class IniFile
' API functions
Private Declare Ansi Function GetPrivateProfileString _
Lib "kernel32.dll" Alias "GetPrivateProfileStringA" _
(ByVal lpApplicationName As String, _
ByVal lpKeyName As String, ByVal lpDefault As String, _
ByVal lpReturnedString As System.Text.StringBuilder, _
ByVal nSize As Integer, ByVal lpFileName As String) _
As Integer
Private Declare Ansi Function WritePrivateProfileString _
Lib "kernel32.dll" Alias "WritePrivateProfileStringA" _
(ByVal lpApplicationName As String, _
ByVal lpKeyName As String, ByVal lpString As String, _
ByVal lpFileName As String) As Integer
Private Declare Ansi Function GetPrivateProfileInt _
Lib "kernel32.dll" Alias "GetPrivateProfileIntA" _
(ByVal lpApplicationName As String, _
ByVal lpKeyName As String, ByVal nDefault As Integer, _
ByVal lpFileName As String) As Integer
Private Declare Ansi Function FlushPrivateProfileString _
Lib "kernel32.dll" Alias "WritePrivateProfileStringA" _
(ByVal lpApplicationName As Integer, _
ByVal lpKeyName As Integer, ByVal lpString As Integer, _
ByVal lpFileName As String) As Integer
Dim strFilename As String
' Constructor, accepting a filename
Public Sub New(ByVal Filename As String)
strFilename = Filename
End Sub
' Read-only filename property
ReadOnly Property FileName() As String
Get
Return strFilename
End Get
End Property
Public Function GetString(ByVal Section As String, _
ByVal Key As String, ByVal [Default] As String) As String
' Returns a string from your INI file
Dim intCharCount As Integer
Dim objResult As New System.Text.StringBuilder(256)
intCharCount = GetPrivateProfileString(Section, Key, _
[Default], objResult, objResult.Capacity, strFilename)
If intCharCount > 0 Then GetString = _
Left(objResult.ToString, intCharCount)
End Function
Public Function GetInteger(ByVal Section As String, _
ByVal Key As String, ByVal [Default] As Integer) As Integer
' Returns an integer from your INI file
Return GetPrivateProfileInt(Section, Key, _
[Default], strFilename)
End Function
Public Function GetBoolean(ByVal Section As String, _
ByVal Key As String, ByVal [Default] As Boolean) As Boolean
' Returns a boolean from your INI file
Return (GetPrivateProfileInt(Section, Key, _
CInt([Default]), strFilename) = 1)
End Function
Public Sub WriteString(ByVal Section As String, _
ByVal Key As String, ByVal Value As String)
' Writes a string to your INI file
WritePrivateProfileString(Section, Key, Value, strFilename)
Flush()
End Sub
Public Sub WriteInteger(ByVal Section As String, _
ByVal Key As String, ByVal Value As Integer)
' Writes an integer to your INI file
WriteString(Section, Key, CStr(Value))
Flush()
End Sub
Public Sub WriteBoolean(ByVal Section As String, _
ByVal Key As String, ByVal Value As Boolean)
' Writes a boolean to your INI file
WriteString(Section, Key, CStr(CInt(Value)))
Flush()
End Sub
Private Sub Flush()
' Stores all the cached changes to your INI file
FlushPrivateProfileString(0, 0, 0, strFilename)
End Sub
End Class