Automatic signature extraction failed

[j75]

...when trying to download https://www.youtube.com/watch?v=lUGgXvhLKE4

[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['--verbose', 'https://www.youtube.com/watch?v=lUGgXvhLKE4']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2014.07.11.3
[debug] Python version 2.7.6 - Linux-3.13.0-30-generic-x86_64-with-Ubuntu-14.04-trusty
[debug] Proxy map: {}
[youtube] Setting language
[youtube] lUGgXvhLKE4: Downloading webpage
[youtube] lUGgXvhLKE4: Downloading video info webpage
[youtube] lUGgXvhLKE4: Extracting video information
[youtube] lUGgXvhLKE4: Encrypted signatures detected.
[youtube] encrypted signature length 84 (40.43), itag 22, html5 player en_US-vfl5aDZwb
[youtube] lUGgXvhLKE4: Downloading js player vfl5aDZwb
WARNING: Writing cache to u'/home/marian.deb/.cache/youtube-dl/youtube-sigfuncs/js_vfl5aDZwb_84.json' failed: Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 391, in _extract_signature_function
cache_res = res(test_string)
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 449, in
return lambda s: initial_function([s])
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 113, in resf
res = self.interpret_statement(stmt, local_vars)
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 45, in interpret_statement
v = self.interpret_expression(expr, local_vars, allow_recursion)
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 58, in interpret_expression
val = local_vars[m.group('in')]
KeyError: u'go'

ERROR: Automatic signature extraction failed: Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 883, in _decrypt_signature
return func(s)
File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 449, in
return lambda s: initial_function([s])
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 113, in resf
res = self.interpret_statement(stmt, local_vars)
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 45, in interpret_statement
v = self.interpret_expression(expr, local_vars, allow_recursion)
File "/usr/lib/python2.7/dist-packages/youtube_dl/jsinterp.py", line 58, in interpret_expression
val = local_vars[m.group('in')]
KeyError: u'go'