请高手帮忙.我写的VB出现问题

第一个按钮代码
Private Sub Command1_Click()
 Dim EXAPP As Excel.Application
 Dim WB As Excel.Workbook
 Dim sht As Excel.Worksheet
 Set EXAPP = CreateObject("excel.application")
 Set WB = EXAPP.Workbooks.Open("d:\成绩表.xls")
 Set sht = WB.Worksheets("Sheet1")
Range("N2").Select
     ActiveCell.FormulaR1C1 = "=SUM(RC[-8]:RC[-1])"
    Range("N2").Select
    Selection.AutoFill Destination:=Range("N2:N641"), Type:=xlFillDefault
    Range("N2:N641").Select
    ActiveWindow.SmallScroll Down:=-9
 Form1.Caption = sht.Range("B5").Value '从表格取值
 'WB.Save'保存编辑后的文件
 WB.Close
 Set sht = Nothing
 Set WB = Nothing
 Set EXAPP = Nothing
 End Sub
第二个按钮代码
Private Sub Command2_Click()
 Dim EXAPP As Excel.Application
 Dim WB As Excel.Workbook
 Dim sht As Excel.Worksheet
 Set EXAPP = CreateObject("excel.application")
 Set WB = EXAPP.Workbooks.Open("d:\成绩表.xls")
 Set sht = WB.Worksheets("总表")
  Range("A2:V800").Select
    Selection.Sort Key1:=Range("T3"), Order1:=xlDescending, Header:=xlGuess, _
        OrderCustom:=1, MatchCase:=False, Orientation:=xlTopToBottom, SortMethod _
        :=xlPinYin, DataOption1:=xlSortNormal   
 Set sht = Nothing
 Set WB = Nothing
 Set EXAPP = Nothing
End Sub
只要执行第二个按钮，红色部分就提示错误，是什么原因请高手帮忙下