求助高手，出现“实时错误91,对象变量或with或块变量未设置”，怎么解决？
求助高手，出现“实时错误91,对象变量或with或块变量未设置”，怎么解决？ 我编写一段高考成绩查询系统，运行时提示:'实时错误91,对象变量或with或块变量未设置',请问如何解决？，谢谢
Private Sub Adodc1_WillMove(ByVal adReason As ADODB.EventReasonEnum, adStatus As ADODB.EventStatusEnum, ByVal pRecordset As ADODB.Recordset)
End Sub
Private Sub Form_Load()
ado.ConnectionString = 'Provider=Microsoft.Jet.OLEDB.4.0;Data Source=' + App.Path + '\db1.mdb'
ado.CommandType = adCmdText
ado.RecordSource = 'select * from db1'
ado.Refresh '程序运行至此，出现出错提示'对象的方法IAdodc失败'
End Sub
Private Sub Label2_Click()
ado.Recordset.Close '程序运行至此，出现出错提示'实时错误91,对象变量或with或块变量未设置'
ado.Recordset.Open 'select * from db1 where 准考证号= ' ' + Txt1 + '’' '
If ado.Recordset.EOF Then
MsgBox '数据库中没有你想查询的', 16, '错误' Else
Form2.Txt1.Text = ado.Recordset.Fields(' 姓名' ).Value
Form2.Txt2.Text = ado.Recordset.Fields('性别').Value
Form2.Txt3.Text = ado.Recordset.Fields('语文').Value
Form2.Txt4.Text = ado.Recordset.Fields('数学').Value
Form2.Txt5.Text = ado.Recordset.Fields('英语').Value
Form2.Txt6.Text = ado.Recordset.Fields('综合').Value
Form2.Txt7.Text = ado.Recordset.Fields('总分').Value
Form2.Txt8.Text = ado.Recordset.Fields('录取学校').Value
Form2.Show
Form2.Caption = RTrim(ado.Recordset.Fields('姓名').Value) & '的成绩'
End If
End Sub
