Dynamic dashboard - Target Unreachable, identifier 'dashboardBacker' resolved to null

[kropek as]

Hi,
I try to use this solution http://wobblycogs.co.uk/index.php/computing/jee/49-dynamic-dashboard-with-primefaces , but when i try to run it i get that error:

Target Unreachable, identifier 'dashboardBacker' resolved to null

I tryed change scope and that still dont want to work ;/ Can anybody try to help me with that?
I use library primefaces 2.2.1 and server GlassFish 3.1.