Finally I got some hours to rest and play my guitar. Then I opened my xterm and tried to run tuxguitar(to practice: ysellamaperu.mid from "El Rincón Musical Peruano") but.... There is a terrible and poor in expression "bug":

Exception in thread "main"
java.lang.NoClassDefFoundError:
org/eclipse/swt/widgets/Layout

Then I googled, tried with strace, and remembered some recent dpkg problems with "ln -s" (or dinamic links) The way i fixed this is:

# sudo rm /etc/alternatives/swt.jar
# sudo ln -s /usr/share/java/swt-gtk-3.2.2.jar /etc/alternatives/swt.jar

And please let me play my guitar in peace!!!

Blesings :D