我用VB和ACCESS做的系统,怎么一直提示"对象打开时,不允许操作"??

第一次查询可以正常进行,再点确定就开始提示错误,代码如下:
Private Sub Command1_Click()
Dim conn As New ADODB.Connection
Dim sql As String
On Error GoTo loaderror
If Check1.Value = vbChecked Then
sql = "车牌号='" & Trim(Text1.Text & "") & "'"
End If

conn.Open "provider=Microsoft.Jet.OLEDB.4.0; data source=" & App.Path & "\database.mdb"
If Trim(sql) = "" Then
MsgBox "请选择查询方式!", vbOKOnly + vbExclamation
Exit Sub
End If
sql = "select * from 缴费情况 where " & sql
rs_findjf.CursorLocation = adUseClient
rs_findjf.Open sql, conn, adOpenKeyset, adLockPessimistic
DataGrid1.AllowAddNew = False
DataGrid1.AllowDelete = False
DataGrid1.AllowUpdate = False
If rs_findjf.RecordCount = 0 Then
MsgBox "查询不到该车辆缴费信息!", vbOKOnly + vbExclamation
Else
cmdupdate.Enabled = False
cmdcancel.Enabled = False
Set DataGrid1.DataSource = rs_findjf
Exit Sub
loaderror:
MsgBox Err.Description
End If

End Sub

你第一次已经把CONN打开了，而且程序结束的时候并没有关闭他，所以当你再次打开的时候会提醒你，再添加一句在程序结尾处
conn.close

同问。。。