Hjælp med fejlmeddelelse

Hvorfor får jeg fejl meddelelsen:
HTTP 500 - Intern serverfejl
Internet Explorer, ved denne kode:
<% mode = request("mode") %>
<%
dim mode
mode = request.querystring("mode")
if mode = "" or mode = "news" then %>
<!--#include file="admin/news/default.asp"-->
<% elseif mode = "tagwall" then %>
<!--#include file="admin/tagwall/default.asp"-->
<% elseif mode = "links" then %>
<!--#include file="admin/links/default.asp"-->
<% elseif mode = "downloads" then %>
<!--#include file="downloads/default.asp"-->
<% elseif mode = "babes" then %>
<!--#include file="images/babes/default.asp"-->
<% elseif mode = "graffiti" then %>
<!--#include file="images/graffiti/default.asp"-->
<% elseif mode = "graphic" then %>
<!--#include file="images/graphic/default.asp"-->
<% elseif mode = "funpic" then %>
<!--#include file="fun/images/default.asp"-->
<% elseif mode = "clips" then %>
<!--#include file="fun/clips/default.asp"-->
<% elseif mode = "flash" then %>
<!--#include file="fun/flash/default.asp"-->
<% elseif mode = "games" then %>
<!--#include file="fun/games/default.asp"-->
<% elseif mode = "sounds" then %>
<!--#include file="fun/sounds/default.asp"-->
<% elseif mode = "mig" then %>
<!--#include file="mig/default.asp"-->
<% elseif mode = "kontakt" then %>
<!--#include file="kontakt/default.asp"-->
<% elseif mode = "admin" then %>
<!--#include file="admin/default.asp"-->

<%
else
response.write("Der opstod enten fejl, eller siden du prøver at åbne eksisterer ikke. Beklager.")
end if
%>