Video download error: http://vk.com/videos47465571

[video-dl]

An error occurred while downloading the following video: http://vk.com/videos47465571
This is the output of youtube-dl --verbose

[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'--verbose', u'-J', u'http://vk.com/videos47465571']
[debug] Encodings: locale ANSI_X3.4-1968, fs ANSI_X3.4-1968, out None, pref ANSI_X3.4-1968
[debug] youtube-dl version 2015.12.21
[debug] Python version 2.7.6 - Linux-3.19.0-39-generic-x86_64-with-Ubuntu-14.04-trusty
[debug] exe versions: avconv 9.18-6, avprobe 9.18-6
[debug] Proxy map: {}
WARNING: Your copy of avconv is outdated and unable to properly mux separate video and audio files, youtube-dl will download single file media. Update avconv to version 10-0 or newer to fix this.
WARNING: Your copy of avconv is outdated and unable to properly mux separate video and audio files, youtube-dl will download single file media. Update avconv to version 10-0 or newer to fix this.
WARNING: Your copy of avconv is outdated and unable to properly mux separate video and audio files, youtube-dl will download single file media. Update avconv to version 10-0 or newer to fix this.
WARNING: Your copy of avconv is outdated and unable to properly mux separate video and audio files, youtube-dl will download single file media. Update avconv to version 10-0 or newer to fix this.
WARNING: Your copy of avconv is outdated and unable to properly mux separate video and audio files, youtube-dl will download single file media. Update avconv to version 10-0 or newer to fix this.
ERROR: Video 47465571_171303122 is only available for registered users, use --username and --password options to provide account credentials.
Traceback (most recent call last):
File "/usr/local/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 665, in extract_info
ie_result = ie.extract(url)
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/common.py", line 291, in extract
return self._real_extract(url)
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/vk.py", line 251, in _real_extract
raise ExtractorError(error_msg % video_id, expected=True)
ExtractorError: Video 47465571_171303122 is only available for registered users, use --username and --password options to provide account credentials.