ToME: the Tales of Maj'Eyal

I was fighting in the Charred Scar vs. the Grand Corruptor as a paradox mage. He transported me to the Fearscape, and I ended up dying, but, in the process I dealt enough damage for him to make the offer to attack Ziguranth. So I'm in the Eidolon plane, and his dialogue box popped up. I guess it caused some kind of conflict because I wasn't in the Fearscape/Charred Scar anymore. Long story short, I can't accept/decline his offer and I can't back out of the offer in any way. So I'm stuck.

I have heard about this happening before. From what I remember, if you force-quit the game and then open it again, you will still be on the Eidolon Plane (because it should have auto-saved when you changed level), but the offer dialogue box will be gone, so you can keep playing. But you won't get another chance to accept the offer, apparently.