I saw some threads a/b youtube-viewer not working in Antix without having to do some special package upgrades and noticed that it was not working due to some Perl issues, being built for v5.14 whereas the current Perl is v5.18.2. Being a"perl guy", I had to dig deeper and sure enough, some XS (C) functions were built for v5.14. Here's how I solved the problem:

As root:
1) perl -MCPAN -e"install Gtk2"
#NOTE: This takes awhile recompiling all the"C"-language (XS) parts.

2) vi (edit) /usr/bin/youtube-viewer and add the following 2 lines just above the one that says"require WWW::YoutubeViewer;":

use lib '/usr/local/lib/perl/5.14.2/'; #JWT:NEXT 2 ADDED 20140827:
use lib '/usr/local/lib/perl/5.18.2/';

3) invoke as:
youtube-viewer <youtube-short-url> #for mplayer (default) -OR-
youtube-viewer --mplayer=/usr/bin/vlc --mplayer-args=-q <youtube-short-url> #for vlc

4) You can also do the same patch to gtk-youtube-viewer!

Please, check the workaround suggested here:
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"antix.freeforu ms.org/post36770.html#p36770"
linktext was:"antix.freeforu ms.org/post36770.html#p36770"
====================================
and post if it works for you.

By the way, after"apt-get update" and"apt-get dist-upgrade" today (which upgraded perl to v5.20.0), youtube-viewer stopped working again. This time reason is that /usr/bin/mplayer shows"error while loading shared libraries: libdvdnavmini.so.4: cannot open shared object file: No such file or directory"

After a quick search found this:
========= SCRAPER REMOVED AN EMBEDDED LINK HERE ===========
url was:"http://crunchbang.org/forums/viewtopic.php?pid=390892"
linktext was:"http://crunchbang.org/forums/viewtopic.php?pid=390892"
====================================
and applied the suggested workaround
Now it's working again. Do you know a better approach for solving this kind of problems? (noob question)