Reconstructing Impetusium bug, please halp me

I've got a big problem with my campaign-quest. I'll start from the beginning:

I started the "Reconstructing Impetusium"-quest, and got Umkata's sword pretty quickly. I started exploring a bit, and saw that someone already had summoned Umkata not only once, but two times, so I dealt with the two Umkatas pretty quickly. Now to the bug: I can't complete the quest. Whenever I talk with Gulkalla, it's like I'm talking to the tombstone. "I summon thee, Umkata" and so on. And the earrings and bones wont drop anymore, because I've done that step according to my questlog, and so I can't finish the quest at all.

Halp plix plax.

 

This quest is working fine.
Umkata's Bones I got from first Brutal Black Claw Bodyguard I killed.
Umkata's Weapon I got from 2nd Cyclone Spirit I killed.
Umkata's Earring can be gotten from the jewel box located in Impetusium.

Went to Umkata's Grave - needed to relog to make the tombstone show. After killing Umkata went back to Gulkalla. Gulkalla does say "I summon thee Umkata" Just click on that to finish the quest.