There are a new commercial version, free version in few days we upgrade it, contact with me in comercial@tierravirtual.net
Que tal, puedes enviar el ticket de error a http://www.meesolutions.com/support/meenews
Y te dire como solucionar el problema de la version premium un saludo.
firt of all you must delete the line
<?php TVNewsletter::activatenewsletterplugin()?>
not works.
and try to use widget, and i dont know in 3.1 alpha but i try to solve this problem now.
Download new version, doimih, all works ok