The latest version of AnyDVD is 220.127.116.11 beta, safe for anyone to use and the trial is allowed for this beta. http://club.myce.com/f173/slysoft-anydvd-hd-updates-275818/index5.html#post2525894
It definitely will decrypt Avatar.
Avatar was released on dvd on April 22, 2010. The version of AnyDVD that you mentioned, 18.104.22.168 was released May 31, 2010 so it should have no problem with this movie either.
By the way Mellwww, please don’t post the same question in two different subforums. It causes confusion on where to answer you and is against the rules here. I’ve merged your two posts into one.