Probleempje met openen van formulier

' Declare necessary API routines:
Declare Function FindWindow Lib "Gebruiker32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As Long) As Long
Declare Function SendMessage Lib "Gebruiker32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _
    ByVal lParam As Long) As Long

Sub GetExcel()
Dim MyXL As Object    ' Variable to hold reference to Microsoft Excel.
Dim ExcelWasNotRunning As Boolean    ' Flag for final release.

    ' Test to see if there is a copy of Microsoft Excel already running.
    On Error Resume Next    ' Defer error trapping.
    ' Getobject function called without the first argument returns a reference to an instance of the application.
    ' If the application isn't running, an error occurs.
    Set MyXL = GetObject(, "Excel.Application")
    If Err.Number <> 0 Then ExcelWasNotRunning = True
    Err.Clear    ' Clear Err object in case error occurred.

    ' Check for Microsoft Excel. If Microsoft Excel is running, enter it into the Running Object table.
    DetectExcel

    ' Set the object variable to reference the file you want to see.
    Set MyXL = GetObject("c:\vb4\MIJNTEST.XLS")

    ' Show Microsoft Excel through its Application property. Then show the actual window containing the file using the Windows collection of the MyXL object reference.
    MyXL.Application.Visible = True
    MyXL.Parent.Windows(1).Visible = True
    '      Do manipulations of your  file here. ...
    ' If this copy of Microsoft Excel was not running when you started, close it using the Application property's Quit method.
    If ExcelWasNotRunning = True Then
        MyXL.Application.Quit
    End If

    Set MyXL = Nothing    ' Release reference to the application and spreadsheet.
End Sub

Sub DetectExcel()
' Procedure dectects a running Excel and registers it.
Const WM_USER = 1024
Dim hWnd As Long
    ' If Excel is running this API call returns its handle.
    hWnd = FindWindow("XLMAIN", 0)
    If hWnd = 0 Then    ' 0 means Excel not running.
        Exit Sub
    Else
        ' Excel is running so use the SendMessage API function to enter it in the Running Object Table.
        SendMessage hWnd, WM_USER + 18, 0, 0
    End If
End Sub