[Problem]Take function in Quests not working

[Human 20]

Hello all,
I have problem with dragging an item and giving to any npc 
1) First is let us consider Demon tower 
at seal floor when 50084 that is Unlock key is given to Ancient seal 20073 it must accept or take and dissapears its not happening 
nothing does.. 
and time wasted.. 

2) In 20093 npc that is stone remover when i drag him any weapon or armor he is not accepting to remove those stones.. rather nothing happens 

No syserr error in both cases 

and in many cases 

Hope i get solution 

[Human 20]

any one ???