新手求指教！！请大师们帮助！
用VB做了一个简单的EXCEL格式修改软件，但是发现第一次运行正常，第二次再拖曳文件到上面就出现了424，无法取得对象了。纠结了很久不知道怎么搞。请假大师们！错误定位在下图：
程序代码：Private Sub Form_Load()
Me.OLEDropMode = 1
End Sub
Private Sub Form_OLEDragDrop(DATA As DataObject, Effect As Long, Button As Integer, Shift As Integer, X As Single, Y As Single)
If DATA.Files.Count < 1 Then Exit Sub
Dim tFile As String
tFile = DATA.Files.Item(1)
If UCase(Right(tFile, 4)) <> ".XLS" Then
MsgBox "拖放的文件不是Excel文件", vbInformation
Exit Sub
End If
Dim xlApp As Excel.Application
Dim xlBook As Excel.Workbook
Dim xlSheet As Excel.Worksheet
Set xlApp = CreateObject("Excel.Application") '
' 隔行添加一行
Set xlBook = xlApp.Workbooks.Open(tFile) '打开已经存在的EXCEL工件簿文件
xlApp.Visible = True '设置EXCEL对象可见（或不可见）
Set xlSheet = xlBook.Worksheets("Sheet1") '设置活动工作表
With xlSheet
p = [a20].End(xlUp).Row
For i = 5 To p * 2 Step 2
Rows(i & ":" & i).Insert Shift:=xlDown
Next i
Range("A1").Select
' 添加签到字符
'
'
Range("B5").Select
ActiveCell.FormulaR1C1 = "签名"
With ActiveCell.Characters(Start:=1, Length:=2).Font
.Name = "宋体"
.FontStyle = "常规"
.Size = 11
.Strikethrough = False
.Superscript = False
.Subscript = False
.OutlineFont = False
.Shadow = False
.Underline = xlUnderlineStyleNone
.ColorIndex = xlAutomatic
End With
Range("B6:B7").Select
Range("B7").Activate
ActiveCell.FormulaR1C1 = "签名"
With ActiveCell.Characters(Start:=1, Length:=2).Font
.Name = "宋体"
.FontStyle = "常规"
.Size = 11
.Strikethrough = False
.Superscript = False
.Subscript = False
.OutlineFont = False
.Shadow = False
.Underline = xlUnderlineStyleNone
.ColorIndex = xlAutomatic
End With
Range("B8:B9").Select
Range("B9").Activate
ActiveCell.FormulaR1C1 = "签名"
With ActiveCell.Characters(Start:=1, Length:=2).Font
.Name = "宋体"
.FontStyle = "常规"
.Size = 11
.Strikethrough = False
.Superscript = False
.Subscript = False
.OutlineFont = False
.Shadow = False
.Underline = xlUnderlineStyleNone
.ColorIndex = xlAutomatic
End With
Range("B10:B11").Select
Range("B11").Activate
ActiveCell.FormulaR1C1 = "签名"
With ActiveCell.Characters(Start:=1, Length:=2).Font
.Name = "宋体"
.FontStyle = "常规"
.Size = 11
.Strikethrough = False
.Superscript = False
.Subscript = False
.OutlineFont = False
.Shadow = False
.Underline = xlUnderlineStyleNone
.ColorIndex = xlAutomatic
End With
Range("B11").Select
' 添加表头
'
'
'
Range("A1:I1").Select
ActiveCell.FormulaR1C1 = "教学班任课教师签到表 第 周"
Range("F7").Select
'
' 删除后几行
'
Rows("12:15").Select
Range("A15").Activate
Selection.Delete Shift:=xlUp
Range("A12:I12").Select
' 添加备注
'
'
Range("A12:I12").Select
ActiveCell.FormulaR1C1 = _
"备注：……"
With ActiveCell.Characters(Start:=1, Length:=114).Font
.Name = "宋体"
.FontStyle = "常规"
.Size = 11
.Strikethrough = False
.Superscript = False
.Subscript = False
.OutlineFont = False
.Shadow = False
.Underline = xlUnderlineStyleNone
.ColorIndex = xlAutomatic
End With
Range("F10").Select
Rows("12:12").RowHeight = 26.25
' 设置页边距
'
With ActiveSheet.PageSetup
.PrintTitleRows = ""
.PrintTitleColumns = ""
End With
ActiveSheet.PageSetup.PrintArea = ""
With ActiveSheet.PageSetup
.LeftHeader = ""
.CenterHeader = ""
.RightHeader = ""
.LeftFooter = ""
.CenterFooter = ""
.RightFooter = ""
.LeftMargin = Application.InchesToPoints(0.748031496062992)
.RightMargin = Application.InchesToPoints(0.748031496062992)
.TopMargin = Application.InchesToPoints(0.393700787401575)
.BottomMargin = Application.InchesToPoints(0.196850393700787)
.HeaderMargin = Application.InchesToPoints(0.511811023622047)
.FooterMargin = Application.InchesToPoints(0.511811023622047)
.PrintHeadings = False
.PrintGridlines = False
.PrintComments = xlPrintNoComments
.PrintQuality = 600
.CenterHorizontally = False
.CenterVertically = False
.Orientation = xlLandscape
.Draft = False
.PaperSize = xlPaperA4
.FirstPageNumber = xlAutomatic
.Order = xlDownThenOver
.BlackAndWhite = False
.Zoom = 100
.PrintErrors = xlPrintErrorsDisplayed
End With
' 合适行高
Columns("C:C").Select
Range("C3").Activate
Selection.Rows.AutoFit
Rows("12:12").RowHeight = 27.75
End With
xlBook.Close (True) '关闭工作簿
xlApp.Quit '结束EXCEL对象
Call MsgBox("转换完成", vbInformation, "提示")
End Sub
