Help! I'm stuck

I've completed the "ice horn" quest, but according to the walkthrough the boss I just beat was supposed to steal both horns and then I'm supposed to chase him to the cave to the north. But I never saw him re-steal the horns and Iwhen I go to the northern cave there is a fire wall that blocks my path. I can't go any farther, and I've done everything I can on this level. I've re-visited all the places I've been before twice and I', getting frustrated. Any help is appreciated.

Talk to the dwarf near the altar thingie.

Talk to the altar dwarf.

I have, several times. I can see the ice horn sitting on the altar. I've talked to everybody I can find. I've even re-visited the first town and worked my way back to the dwarves. I can't go on until I complete this task.

Then walk up to the altar and examine the horn.