这段程序是教程书本里的例子。但动行时总是出现500错误，，怎样解决呢?

源代码如上：
Response.Write ""
' 显示数据库的域名
For intI = 0 to intFCount
Response.Write ""
Next
Response.Write ""
intCount = 0
' 显示数据库内容
Do While Not objRS.EOF AND intCount < intStopRec
intCount = intCount + 1
If intCount >= intStartRec Then
Response.Write ""
' 显示每个记录的域
For intI = 0 to intFCount
If objRS.Fields(intI).value <> "" Then
Response.Write ""
Else
Response.Write ""
End If
Next
Response.Write ""
End If
objRS.MoveNext ' 移到下一个记录
Loop
Response.Write "

" & objRS(intI).Name & "
" & objRS.Fields(intI).value & "	---

"
End If
objRS.Close ' 关闭记录集合
Set objRS = Nothing
objDBConn.Close ' 关闭数据库连接
Set objDBConn = Nothing
' 目前的页数
Response.Write "目前为第" & intPageNo & "页/总共有" & intMaxPageCount & "页
"
' 建立数字的超级链接
Dim strURL, intPreviousPageNo, intNextPageNo
For intI = 1 To intMaxPageCount
strURL = "" & intI & ""
Response.Write strURL & " "
If intI mod 10 = 0 Then
Response.Write "
"
End If
next
' 上一页的超级链接
intPreviousPageNo = intPageNo - 1
If intPreviousPageNo > 0 Then
strURL = "上一页"
Response.Write strURL & " "
End If
' 下一页的超级链接
intNextPageNo = intPageNo + 1
If intNextPageNo <= intMaxPageCount Then
strURL = "下一页"
Response.Write strURL & " "
End If
%>

错误信息如下：
Microsoft OLE DB Provider for ODBC Drivers 错误 '80004005'

[Microsoft][ODBC 驱动程序管理器] 未发现数据源名称并且未指定默认驱动程序

错误的行号是27行

24：strDBDSN = "DSN=USERS_list;uid=lisi;pwd=1234"
25：strSQL = "SELECT * FROM USERS"
26：Set objDBConn = Server.CreateObject("ADODB.Connection")
27：objDBConn.Open strDBDSN