Ah, in that case, I understand. It's highly annoying when you've found or bookmarked some video and then two days later, they've either taken it down or their account was suspended over copyrights or something as silly as that.
If it's important enough, then you can try using the same search parameters again to see whether somebody else has also uploaded a copy of that particular video, or maybe you can find it at Vimeo or DailyMotion?
Just a thought.