In Sevenkeeps I started by doing the necessary hack'n slash of hornets, spiders etc and then I went to see the king. After the cutscene I talked with everybody and I got the main quest "The ambassador of the dwarves" but when I come to see the dwarven ambassador he won't talk to me. And as it's a main quest I cannot skip it. Thanks for any useful ideas.

Sorry for this wrong question. I've finally noticed that the dwarven ambassador is so far the only NPC that interacts with you even without an exclamation point.