Two quests : type Missions not working for me

Hello everyone, i think that this is the good place to post, if not, my apologies ^^

I am having troubles with two Missions :

The first one is "A giganstic weapon" (Une arme enorme, en français)
Bug : when i am trying to use the book in Anganhenk nothing happen, no matter what i do or re-do...
Is there a solution?

The second one is "Flying report"? (Reconnaissance aérienne, en français)
Bug : in verteron u should lure a krall boss to an npc in order to questionne him, i have weakened him but when i reach the npc, nothing happen... Ant yet this is the good mob.

For informations i am LVL55 is that a problem?
I really want to do those quests, thanx for ur answers!

Best regards