Moment of Inertia in Mass Properties

I have been trying to have SolidWorks 2010 provide me a Moment of Inertia (MOI) for an assembly I have created, but it won't provide it for the entire assembly.  I am not sure why it won't provide it.  Many of the parts I have assigned a specific mass, some I have not.  So far it seems that the mass assignments cause SolidWorks to NOT provide an MOI, whereas it would if I hadn't assigned a mass. 

Can anyone provide any insight? 

Thanks

Michael

(650) 291-6225

SolidworksAssemblies