404 Custom Error In IIS 6.0 And Language Does Not Work

I've created a 404 error page called 404.aspx which works fantastic when I call it manually.But after setting the "custom error" in web.config and IIS 6.0. It doesn't work properly.for example, If I type the URL the wrong way, it won't work and a message like the one below,

Location: **http://domain/anything** (without an extension)
Line Number 1, Column 2:<%@ page language="C#" masterpagefile="~/Public.master" autoeventwireup="true" inherits="_404, App_We
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<input type='hidden' name='ID[1]' value='199797' />
<input type='hidden' name='URL[1]' value='http://stackoverflow.com/questions/5047449/iis-overriding-custom-404-error-page-in-asp-net' />
<input type='hidden' name='CAT[1]' value='ASP.NET' />
<input type='hidden' name='BOARD[1]' value='stackoverflow' />
<input type='hidden' name='P_DATE[1]' value='Feb 18 at 22:57' />
<input type='hidden' name='RANDOM[1]' value='acx2qwxlK' />
<input type='hidden' name='REPLIES[1]' value='1' />
[code]...

with no .aspx then IIS7 takes matters into its own hands and I get the lovely error page that IIS7 comes with. The goal is that the site redirects with only a 404 status code (so not a 200, or a 302 redirect). ..but htere is no data coming out