服务器asp下载的问题，小文件正常，大文件就500错误，下载是asp语言执行，代码如下

代码如下：

<!--#include file="Include/FY.conn.asp" -->
<!--#include file="Include/FY.Common.Front.Asp" -->
<!--#include file="Include/FY.Write.Asp"-->
<%Call FY_IP_Y(2)
If FY_Config(13)=1 And (Request.Cookies(FY_cookies)("AdminName")="" Or Request.Cookies(FY_cookies)("AdminId")="" Or Request.Cookies(FY_cookies)("AdminFlag")="") Then
Response.Write FY_Config(14)
Call CloseConn()
Response.End
End if
If FY_SDown(0)=0 And FY_SDown(1)=0 Then
Response.Write"<script>alert('本站目前是关闭小说下载功能，请使用在线阅读服务。');history.back();</Script>"
Call CloseConn()
Response.End
End if
Dim NovelID,FY_ClassID,FY_NovelName,XSRs,FY_Nove_TXTUrl,xRs,JID
Dim FeiYun_I,rsArray
Dim down_S,Range,FName
FY_ClassID=FY_CLng(trim(request("C")))
NovelID=FY_CLng(trim(request("id")))
JID=FY_CLng(trim(request("J")))
FName=urldecode(trim(request("s")))
'Call CheckComeUrl()
if len(FName)<3 Then
	FName=urldecode(trim(request("n")))
End if
If FY_ClassID<>0 And JID=0 Then
	FY_Nove_TXTUrl=FY_SDown(2)&"/"&FY_ClassID&"/"&NovelID&".txt"
	if FName<>"" And len(FName)>2 Then
		FY_NovelName=FName
	Else
		FY_NovelName=NovelID
	End if
ElseIf FY_ClassID<>0 Then
	FY_Nove_TXTUrl=FY_SDown(2)&"/"&FY_ClassID&"/"&NovelID&"/"&JID&".txt"
	if FName<>"" And len(FName)>2 Then
		FY_NovelName=FName
	Else
		FY_NovelName=NovelID&"_"&JID
	End if
ElseIf FY_ClassID=0 Then
	Response.Write"<script>alert('标签下载调用错误，请将此信息反馈留言给本站站长');history.back();</Script>"
	Call CloseConn()
	Response.End
End if
If FY_NovelName<>"" And FY_Nove_TXTUrl<>"" Then
	If IsExists(FY_Nove_TXTUrl)=False Then
		Response.Write"<script>alert('本书TXT文件暂为生成，请留言或其他方式通知管理员生成本书TXT');history.back();</Script>"
		Call CloseConn()
		Response.End
	Else
		Call CloseConn()
			  Set down_S=CreateObject("Adodb.Stream")  
			  down_S.Mode=3  
			  down_S.Type=1  
			  down_S.Open  
			  down_S.LoadFromFile(server.MapPath(FY_Nove_TXTUrl))  
			   if Err.Number>0 then  
					Reaponse.status="404" 
			   else  
					  Response.ContentType="application/octet-stream"  
					  Response.AddHeader "Content-Disposition:","Attachment;filename="&FY_NovelName&".txt"  
					  Range=Mid(Request.ServerVariables("HTTP_RANGE"),7)  
					  if Range="" then  
							Response.BinaryWrite(down_S.Read)
					  else  
						   S.Postion=Clng(Split(Range,"-")(0))  
						   Response.BinaryWrite(down_S.Read)
					  end if  
			   End if  
			   Response.end
	End if
Else
	Response.Write"<script>alert('下载调用错误，无法获得文件信息，请将此信息反馈留言给本站站长');history.back();</Script>"
	Call CloseConn()
	Response.End
End if
%>

请高手帮忙解答