Webrick transparent proxy

I have a simple proxy server.

require 'webrick' 
require 'webrick/httpproxy' 

s = WEBrick::HTTPProxyServer.new(:Port => 8080,
    :RequestCallback => Proc.new{|req,res| puts req.request_line, req.raw_header})

# Shutdown functionality
trap("INT"){s.shutdown}

# run the beast
s.start

      

        
        
        
      

    

This, in my opinion, does not affect communication in any way. But some sites no longer work. Especially http://lastfm.de the built-in flash players don't work.

The header looks like a link:

- -> http://ext.last.fm/2.0/?api%5Fsig=aa3e9ac9edf46ceb9a673cb76e61fef4&flashresponse=true&y=1269686332&streaming=true&playlistURL=lastfm%3A%2F%2Fplaylist%2Ftrack%2F42620245&fod=true&sk=ee93ae4f438767bf0183d26478610732&lang=de&api%5Fkey=da6ae1e99462ee22e81ac91ed39b43a4&method=playlist%2Efetch
GET http://play.last.fm/preview/118270350.mp3 HTTP/1.1
Host: play.last.fm
User-Agent: Mozilla/5.0 (X11; U; Linux i686; de; rv:1.9.2) Gecko/20100308 Ubuntu/10.04 (lucid) Firefox/3.6
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: de,en-us;q=0.7,en;q=0.3
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Proxy-Connection: keep-alive
Cookie: AnonWSSession=ee93ae4f438767bf0183d26478610732; AnonSession=cb8096e3b0d8ec9f4ffd6497a6d052d9-12bb36d49132e492bb309324d8a4100fc422b3be9c3add15ee90eae3190db5fc
localhost - - [27/Mar/2010:11:38:52 CET] "GET http://www.lastfm.de/log/flashclient/minor/Track_Loading_Fail/Buffering_Timeout HTTP/1.1" 404 7593
- -> http://www.lastfm.de/log/flashclient/minor/Track_Loading_Fail/Buffering_Timeout
localhost - - [27/Mar/2010:11:38:52 CET] "GET http://play.last.fm/preview/118270350.mp3 HTTP/1.1" 302 0

      

        
        
        
      

    

I don't know why or what is breaking the connection.