this quest bug might be worling until now
but try it with the gunpowder
here is the steps
1 take the quest of gun powder
2 colect the first 200
3 use return scrol (any where u have to)
4 put the 200 gunpowder in storege (it can be stored)
5 go to the quest npc (with out the 200) u will take ur EXP GOLD
6 head back to storege get the 200 use return scroll again
7 put it in stroege again
8 go to the npc start conv
u finshed ur quest with the 200 still in store
tip:when the 200 gunpowder is still in store when u start a new a account do those steps but dont do step 2
sry for those many steps it u have too