Flash socket connection to HTTP server

Code is simple and clear:

rs = new Socket();
rs.connect("kirupa.com",80);
rs.writeUTFBytes("GET / 
");
rs.flush();

Most of the servers, including kirupa.com, send response back to me but rapidshare.com is not responding. It connects nicely but gets not response when i send GET command. Have anyone got any clue why rapidshare is not communicating with my flash application, while it communicates nicely with all the browsers.