yea old one is good..
actually keep em both
first while installation and other option in settings
atleast till the widget bug is solved
besides, i dun think its theme related, in pr1.1.1, this used to happen to me alot... the exact replica of the situation would be that sometimes, when i added a new widget, the system would be busy or soemthing leading to the widgets disappearing..
i was kinda new to it so i didnt investigate much