Each of your rigids have a "different" solver?? weird...

By default, when you create your first active rigid object in your scene, Maya creates a default rigid "Solver".

Then, every object you create after that, i.e. polycube2, polycube3 etc. are attached to that same solver unless you tell Maya otherwise.

(at least, that's the way it has always worked for me in 4.0 and 4.5)

You should only have one main rigid solver, for your rigids.

So, for my expression to work, you would have had to select all of your objects that you want rigid, then make them active rigids, then you would have only ONE solver for all of your objects.

hehe... I suck at this too, but my expression worked for me so....
not sure what else I can tell ya....

Sorry.... I'm a tard....