Ok, I have everything up and running.
My fisrt Qt app worked like charm. But I don´t know why, because this:
def __init__(self, parent=None):
#build parent user interface
QtGui.QWidget.__init__(self, parent)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)

if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
myapp = MyForm()
myapp.show()
sys.exit(app.exec_())

Is completely new and there is no explanation on the tutorial:
http://talk.maemo.org/showpost.php?p...8&postcount=59

Any link or guidance?
Thanks!