title: S3cmd not working in ubuntu
body: <p>I have Installed s3cmd on my machine which is ubuntu 11.10 and when i am trying to download some data from s3 it gives me this error, I have also configure s3cmd with the access keys which i have  (.s3cfg file is there in home folder)</p>
  
  <pre><code>!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
      An unexpected error has occurred.
    Please report the following lines to:
     s3tools-bugs@lists.sourceforge.net
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  Problem: KeyError: 'content-length'
  S3cmd:   1.0.0
  
  Traceback (most recent call last):
    File "/usr/bin/s3cmd", line 2006, in &lt;module&gt;
      main()
    File "/usr/bin/s3cmd", line 1950, in main
      cmd_func(args)
    File "/usr/bin/s3cmd", line 513, in cmd_object_get
      response = s3.object_get(uri, dst_stream, start_position = start_position, extra_label = seq_label)
    File "/usr/share/s3cmd/S3/S3.py", line 285, in object_get
      response = self.recv_file(request, stream, labels, start_position)
    File "/usr/share/s3cmd/S3/S3.py", line 691, in recv_file
      size_left = int(response["headers"]["content-length"])
  KeyError: 'content-length'
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
      An unexpected error has occurred.
      Please report the above lines to:
     s3tools-bugs@lists.sourceforge.net
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  </code></pre>