help!!!

<%
    Dim Stream
    Dim Contents
    Dim FileName
    Dim FileExt
    Const adTypeBinary = 1
    FileName = Request.QueryString("FileName")
    if FileName = "" Then
    'Response.Write
    Response.End
    End if

    ' 下面是不希望下载的文件
    FileExt = Mid(FileName, InStrRev(FileName, ".") + 1)
    Select Case UCase(FileExt)
    Case "ASP", "ASA", "ASPX", "ASAX", "MDB"
    'Response.Write
    Response.End
    End Select

    ' 下载这个文件
    Response.Clear
    Response.ContentType = "application/octet-stream"
    Response.AddHeader ("content-disposition", "attachment; filename=" & FileName)
    Set Stream = server.CreateObject("ADODB.Stream")
    Stream.Type = adTypeBinary
    Stream.Open
    Stream.LoadFromFile Server.MapPath(FileName)
    While Not Stream.EOS
    Response.BinaryWrite Stream.Read(1024 * 64)
    Wend
    Stream.Close
    Set Stream = Nothing
    Response.Flush
    Response.End
   %>
 不再支持“Let”和“Set”赋值语句。，什么意思，如何解决？