Sequence of events:

1. I went to Gor'tesh's coronation and accepted his proposal.
2. I found out about the foundry afterwards and proceeded to the the Iron Throne thus breaking the treaty between me and Gor'tesh. I saved the small guys and the Duke.
3. After Iron Throne, I went back to kill Gor'tesh. However he is not at the audience chamber already.
4. I tried going to the morphic pool but the emperor won't let me go without Gor'tesh's stone. (I already have Orin's stone)

So now I am stuck, I scouted the whole bloody map of act 2 and could not find Gor'tesh, hence I do not have his stone which means I cannot proceed with the main story.

Can someone please help me out on this? I could not find any answer with google.