как исправить ошибку при загрузке видео

Вы используете устаревшую версию youtube-dl. Так как YouTube регулярно изменяет свой интерфейс, у youtube-dl есть его собственный механизм обновления. Ввести

sudo youtube-dl -U

обновить. Если это не работает, не стесняйтесь регистрировать ошибку в проекте youtube-dl. Не забывайте включать полный вывод при вызове youtube-dl с -v, как это:

[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['-v', 'http://youtu.be/My2FRPA3Gf8']
[debug] Encodings: locale 'UTF-8', fs 'UTF-8', out 'UTF-8', pref: 'UTF-8'
[debug] youtube-dl version 2014.01.27.2
[debug] Python version 2.6.6 - Linux-2.6.32-274.7.1.el5.028stab095.1-x86_64-with-debian-6.0.8
[debug] Proxy map: {}
[youtube] Setting language
[youtube] My2FRPA3Gf8: Downloading webpage
[youtube] My2FRPA3Gf8: Downloading video info webpage
[youtube] My2FRPA3Gf8: Extracting video information
[youtube] My2FRPA3Gf8: Encrypted signatures detected.
[youtube] encrypted signature length 85 (44.40), itag 22, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 43, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 18, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 5, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 36, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 17, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 84 (41.42), itag 137, html5 player ima-en_US-vflkClbFb
[youtube] My2FRPA3Gf8: Downloading js player vflkClbFb
[youtube] encrypted signature length 84 (41.42), itag 136, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 84 (41.42), itag 135, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 84 (41.42), itag 134, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 84 (41.42), itag 133, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 84 (41.42), itag 160, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 84 (41.42), itag 140, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 84 (41.42), itag 171, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 137, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 136, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 135, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 134, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 133, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 160, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 140, html5 player ima-en_US-vflkClbFb
[youtube] encrypted signature length 85 (44.40), itag 171, html5 player ima-en_US-vflkClbFb
[download] Destination: Miley Cyrus - Wrecking Ball-My2FRPA3Gf8.mp4
[download] 100% of 40.76MiB in 00:04

Попробуйте загрузить видео, используя ссылку, которая отображается в адресной строке веб-браузера ... Этот пост может помочь узнать больше ..

Например: youtube-dl http://www.youtube.com/watch?v=2leg8mUE9rs вместо того, что вы пытались

Попробуйте обновить его:

sudo youtube-dl -U

должны решить ваши проблемы.