sql后台不能用dao?

原mdb文件升级成sql后出错

如下红色代码不能通过,提示"对象变量或with块未设置"如何修改正?是不是不支持dao?转成ado?
升迁成adp和 用mdb链接sql有什么区别?
Private Sub Form_Load()
On Error GoTo ErrForm_Load
     Me.Label25.Caption = Format(Now, "dddd, mmm d yyyy, hh:mm:ss AMPM")
      Dim db As Database, rst As Recordset, nodCurrent As Node
      Dim objTree As TreeView, strText As String, nodRoot As Node
      Dim bk As String
      Set db = CurrentDb
      ' 打开雇员表.
           Set rst = db.OpenRecordset("tbl_通讯录分类", dbOpenDynaset, dbReadOnly)
      ' Create a reference to the TreeView Control.
            Set objTree = Me!TreeView0.Object
      ' 查找第一个上级
      rst.FindFirst "[父号] Is Null"
      ' 向TREEVIEW装入数据
      Do Until rst.NoMatch
         ' 取得NAME
         strText = rst![内容]
         ' TREEVIEW第一层.
         Set nodCurrent = objTree.Nodes.add(, , "a" & rst!序号, _