It first I'm not sure why you need binding at all... You defining all the content and header facet declarativelly.. So just remove it If already using c:foreach for dynamical panels iteration - just pick label and other info from the bean instead of working with UI component instances.
And the exception about not found property looks clear... you just seems not defined accessor methods properly.
Does c:forEach work for you at all - i.e. if you don't use binding to 'obj' - what do you see?