The thing is, Scoreboard is a Vanilla function that Better Questing uses.i update.. create a new world.. but the problem is the same =(
the better quest is buged i don't know why =(
After you try filling some of the trader rank, etc quests (be sure you are hitting Claim on them as well!), please do /scoreboard players list [your minecraft name]
For me, that would be /scoreboard players list caigan
Let me know what it lists.