Icelus, here's how the "mysterious vial/contaminated ore" business played out in my game....
1. Returned to Ghastkill, he takes an ore(I had 8-10 ores) and sends you to Taerom.
2. Taerom takes an ore(but does NOT take a vial{I had 2 vials}) and sends you to Thalantyr.
3. Thalantyr takes a vial(he may have taken an ore, too...I didn't notice) and sez he will send word to
Taerom if he can work up an antidote.
That's it so far. I talked to Taerom again and did not get a dialog option saying he had rx'd any word from Thalantyr. I will try back later in the game just in case that little loose end is on a longer timer.
I'm not a Modder, but what may be happening if the above doesn't play out is that...
A. You need at least 3 ores
B. You need at least 1 vial
C. You need to visit the NPC's in the above order.