Well, now it´s fixed and the problem was that I missunderstand the migration tutorial.
No 2 in the tutorial says: ..., remove all the Joomla 2.5 jevents tables:
I removed ALL LISTED tables but leaved the j25_jevents_catmap beacuse it wasn´t in the list
When I now removed ALL jevent tables the migration workes perfect.
Sorry I have troubled you, and thank you for your patient with an ignorant like me