Thank you very much for your answer. Yes, the existence of the alignment file in the -f b stage was the reason.
I followed the manual more careful and finally I did it. I have two trees with the support values as you said, one can be opened with FigTree, the other (with the braces for the nodes) not. Now I'm facing a more serious problem, the values are quite low, but I believe that I have to make a new question for this. It's not the first time that you are helping me and I'm really grateful for that :)