I found the cause of the problem: if there is a no directory with a cyrillic name in the path of the file ("Загрузки" for example) - problem dissapears.
- Bug#862792: dput: UnicodeDecodeError: 'ascii' codec can't... Aleksey Samoilov
I found the cause of the problem: if there is a no directory with a cyrillic name in the path of the file ("Загрузки" for example) - problem dissapears.