[5分]无效的过程引用或参数

确定的事件过程代码如下

Private Sub cmdOK_Click()
    On Error GoTo out_Excel_Err
    Me.Refresh
    If IsNull(Me.startDate) Then
        MsgBox "请输入开始日期!", vbCritical, "提示"
        Me.startDate.SetFocus
        Exit Sub
    End If
    If IsNull(Me.endDate) Then
        MsgBox "请输入结束日期!", vbCritical, "提示"
        Me.endDate.SetFocus
        Exit Sub
    End If

    If Me.startDate > Me.endDate Then
        MsgBox "开始日期不允许大于结束日期!", vbCritical, "提示"
        Me.startDate.SetFocus
        Exit Sub
    End If

    '方法二,将Access表中的数据写入到Excel报表相对应的单元格
    '需要引用DAO 3.6 和Microsoft EXCEL 9.0 或Microsoft EXCEL 11
    Dim ExcelApp As Excel.Application

    Dim Book As Excel.Workbook
    Dim ws As Worksheet
   
    DoCmd.SetWarnings False
    Dim xlsPath As String
xlsPath = "C:\Users\wenqiang.xia\Desktop\proessMIS" & "\daily mill.xlsx"
'xlsPath = CurrentProject.Path & "\Daily Report.xlsx"

    Set ExcelApp = New Excel.Application
    '打开指定的Sheet表
    Set ws = ExcelApp.Workbooks.Open(xlsPath).Worksheets("Processing")
    '生成daily actual表 daily actual表
    DoCmd.OpenQuery "qrydaily mill", acViewNormal
    Dim rst1 As DAO.Recordset
  
    '检测Excel文件是否存在,如果不存在则提醒
    If Dir(xlsPath) = "" Then
        MsgBox "Daily Report.xls文件不存在,请将Excel文件与mdb文件放在同一目录下", vbCritical, "提示"
        End
    End If

    Set rst1 = CurrentDb.OpenRecordset("daily mill", dbOpenDynaset)
    rst1.MoveFirst
    Do Until rst1.EOF
   Dim a As Integer
   a = DateDiff("day", [startDate], [endDate])
   Dim b As Integer
  If a = 0 Then b = 6 Else: b = a + 6
        ws.Cells(b, 2) = rst1("Tonnes Milled")
        ws.Cells(b, 4) = rst1("CV6# Grade")
        ws.Cells(b, 6) = rst1("CV6# Recovery")
        ws.Cells(b, 8) = rst1("CV6# Gold oz Produced")
      

        rst1.MoveNext
    Loop
    ExcelApp.Visible = True    '显示EXCEL让操作员可以看得见，不然就只是在进程中而不可见
    Set ExcelApp = Nothing
    Set Book = Nothing

out_Excel_Exit:
    Exit Sub

out_Excel_Err:
    MsgBox Error$
    Resume out_Excel_Exit

End Sub

哪位老师有时间能把我检查一下，究竟哪里出问题了，谢谢！