Dim Excel As Object = CreateObject("excel.application")
Dim WB As Object = Excel.Workbooks.Add
 
'Verweis auf Extensibility
Dim Guid As String = "{0002E157-0000-0000-C000-000000000046}", Major As Byte = _
  5, Minor As Byte = 3
 
Dim Auflistung As Object = WB.VBProject.References
 
Auflistung.AddFromGuid(Guid, Major, Minor)
 
Excel.application.visible = True
With WB.VBProject.VBComponents.Add(3)
.Properties("Left") = 50 'diese Zeile verursacht den Fehler
End with