Can't run design study with Linear Component Pattern

I have created an asssembly called Ensamblaje1 where the component Pieza2 has a Linear Component Pattern.

What i'd like to do is to run a design study and see how the maximun stress in the model varies depending on the number of Pieza2 I have.

The problem is that when I run the study, just to see if it works for one and two parts, i get an error.

Could anyone tell me if this is possible?