Dragon blood and scales! (Gothic 2)

All the gifts! In General I have a problem, I never can learn dalyvauti dragon blood and scales. I've found a question related to this topic. Generally it said that there are two Celik who could teach it to you. This Gestata and one dragon hunter who initially is with hunters near the entrance to the valley of mines, and then near the freezing waterfall. So, it said that this dragon hunter can teach you when it is near the entrance and also near the waterfall, but the problem is that when I just met him at the aisle he had not taught, no stupid dialogue about learning, and then I went to find the waterfall found, and he's still not trained. Then I went to the Gestata. Once I started the dialogue with him, he could ask the question how is he to remove scales and drain the blood. I was very happy and pressed, he said he knows it!! HE JUST SAID THAT HE CAN CONTINUE NEBILO NO DIALOGUE ABOUT THE BLOOD AND SCALES! Now I don't know what to do( I thought maybe if I kill the dragon, then I will be able to learn. BUT NO( One time I accidentally preserved at the time of death, and I had to use cheats, maybe it's some bug due to cheats, but I don't think so. In General please help!