Family Sharing error

the only "family sharing" i've heard of is where a game is purchased once on steam and can be played by several different accounts in the same group. However, Rising World does not support this. You have to use the same account you purchased it with in order to play it.

@zfoxfire is right, Family Sharing isn't supported by Rising World. So even if you share your lib with someone else, you will see RW in your lib, but you won't be able to run the game.
Here you find more information about Family Sharing: http://store.steampowered.com/promotion/familysharing