自动化错误，求助？？

Private Sub C1_Click()

    Dim objExcel As Excel.Application
    Dim objWorkBook As Excel.Workbook
   
    Set objExcel = CreateObject("Excel.Application")
   

    Set objWorkBook = objExcel.Workbooks.Add()
    objExcel.Visible = True
   
    '设置活动工作表
    Dim objSheet As Excel.Worksheet
    Set objSheet = objExcel.Worksheets("sheet1")
    objSheet.Cells(1, 1) = "mather" '对单元格赋值
    objWorkBook.SaveAs "D:\aa.xls" '保存
    objWorkBook.Close
    objExcel.Quit
    Set objSheet = Nothing
    Set objWorkBook = Nothing
    Set objExcel = Nothing

End Sub