Unable to cast COM object of type 'Microsoft.Office.Interop.Excel.ApplicationClass' to interface type 'Microsoft.Office.Interop.Excel._Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{000208D5-0000-0000-C000-000000000046}' failed due to the following error: 加载类型库/DLL 时出错。 (Exception from HRESULT: 0x80029C4A (TYPE_E_CANTLOADLIBRARY)).
用VS2010VB.net的程序，已经添加了Microsoft Excel 14.0 Object Library 库了，
按键按下的程序如下，但是程序运行到 appXL.Visible = True就出现了上面的错误
下面是源程序代码，请帮帮忙，谢谢
Imports Excel = Microsoft.Office.Interop.Excel
Public Class Form1
Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
Dim appXL As Excel.Application
Dim wbXl As Excel.Workbook
Dim shXL As Excel.Worksheet
Dim raXL As Excel.Range
appXL = CreateObject("Excel.Application")
appXL.Visible = True
wbXl = appXL.Workbooks.Add
shXL = wbXl.ActiveSheet
End Sub
End Class