Yup, the video is from 2010 so that means the game had changed many times and the warden build did too. Back then it was channeling skill which did dmg. Now it's completely different, well maybe not completely, but most of it changed. It serves another purpose now - it doesn't do damage anymore.
You can find this skill here, it's the last chosen one in the skill tree, google translate might be helpful here
http://www.allodswiki.ru/calc/#!5!131..3…...!a/B!a/B!a/B