RegexNotFoundError: Unable to extract Initial JS player signature function name

[natruiz3555]

I got this error while attempting to download a video:

[youtube] Setting language
[youtube] WK0z87WrhGo: Downloading webpage
[youtube] WK0z87WrhGo: Downloading video info webpage
[youtube] WK0z87WrhGo: Extracting video information
[youtube] WK0z87WrhGo: Encrypted signatures detected.
[youtube] WK0z87WrhGo: Downloading js player vflP2rJ1-
ERROR: Signature extraction failed: Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 479, in _decrypt_signature
    video_id, player_url, s
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 383, in _extract_signature_function
    res = self._parse_sig_js(code)
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 454, in _parse_sig_js
    u'Initial JS player signature function name')
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 391, in _search_regex
    raise RegexNotFoundError(u'Unable to extract %s' % _name)
RegexNotFoundError: Unable to extract Initial JS player signature function name; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.
; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.

I'm running Debian GNU/Linux testing (jessie).

[jaimeMF]

You are probably running and old version of youtube-dl, please read our faq for updating.

If you still have the problem with the last version, please post the output of youtube-dl WK0z87WrhGo --verbose.