I had the same issue with a test forum on 0.8.3 no errors for me but the no permission
Global Sidebar vs Category Sidebar
I think that there used to be a way to do widgets for both global and individual categories. I don't see the ability to do this (anymore?) Is there a way to enable this?
You can register new widget areas but need some theme coding
You will have to fork the theme and modify it to use widgets.
It has some, just not many.