Blocked by Forefront TMG

[ghost]

Error while downloading a video, --verbose yielded following result:
C:\Users\GOooOGLE>youtube-dl.exe --verbose http://www.xvideos.com/video7266839/what_about_the_babies_
[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['--verbose', 'http://www.xvideos.com/video7266839/what_about_the_babies_']
[debug] Encodings: locale cp1252, fs mbcs, out cp437, pref cp1252
[debug] youtube-dl version 2014.04.21.3
[debug] Python version 2.7.5 - Windows-7-6.1.7601-SP1
[debug] Proxy map: {}
[XVideos] 7266839: Downloading webpage
ERROR: Unable to download webpage: HTTP Error 403: Forbidden ( Forefront TMG denied the specified Uniform Resource Locator (URL). ); 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; typeyoutube-dl -U to update.
File "youtube_dl\extractor\common.pyo", line 194, in _request_webpage
File "youtube_dl\YoutubeDL.pyo", line 1211, in urlopen
File "urllib2.pyo", line 410, in open
File "urllib2.pyo", line 523, in http_response
File "urllib2.pyo", line 448, in error
File "urllib2.pyo", line 382, in _call_chain
File "urllib2.pyo", line 531, in http_error_default

[phihag]

This is an error caused by local censorship software, most likely installed by your employer or Internet service provider. And since the video in question is NSFW, that's most likely the cause.

Unfortunately, short of using Tor or a VPN, there is nothing that youtube-dl can (or should) do about the blocking, since the proxy in your case is transparent.