Thanks. 
$ youtube-dl "
http://www.youtube.com/watch?v=dREKkAk628I&feature=related"
[youtube] Setting language
[youtube] dREKkAk628I: Downloading video webpage
[youtube] dREKkAk628I: Downloading video info webpage
[youtube] dREKkAk628I: Extracting video information
Traceback (most recent call last):
  File "/usr/bin/youtube-dl", line 2987, in <module>
    retcode = fd.download(all_urls)
  File "/usr/bin/youtube-dl", line 604, in download
    ie.extract(url)
  File "/usr/bin/youtube-dl", line 844, in extract
    return self._real_extract(url)
  File "/usr/bin/youtube-dl", line 1135, in _real_extract
    'player_url':    player_url,
  File "/usr/bin/youtube-dl", line 571, in process_info
    success = self._do_download(filename, info_dict['url'].encode('utf-8'), info_dict.get('player_url', None))
  File "/usr/bin/youtube-dl", line 775, in _do_download
    stream.close()
AttributeError: 'NoneType' object has no attribute 'close'
p$ youtube-dl '
http://www.youtube.com/watch?v=dREKkAk628I&feature=related'
[youtube] Setting language
[youtube] dREKkAk628I: Downloading video webpage
[youtube] dREKkAk628I: Downloading video info webpage
[youtube] dREKkAk628I: Extracting video information
Traceback (most recent call last):
  File "/usr/bin/youtube-dl", line 2987, in <module>
    retcode = fd.download(all_urls)
  File "/usr/bin/youtube-dl", line 604, in download
    ie.extract(url)
  File "/usr/bin/youtube-dl", line 844, in extract
    return self._real_extract(url)
  File "/usr/bin/youtube-dl", line 1135, in _real_extract
    'player_url':    player_url,
  File "/usr/bin/youtube-dl", line 571, in process_info
    success = self._do_download(filename, info_dict['url'].encode('utf-8'), info_dict.get('player_url', None))
  File "/usr/bin/youtube-dl", line 775, in _do_download
    stream.close()
AttributeError: 'NoneType' object has no attribute 'close'
is my laptop lack something? some module? 
I tried the 'URL' and "URL" 
Thanks,