Matrix problem with multiplication

Hi,
I am using Rhino 5. I am wondering that is there something wrong with what I do below? I only multiply a number in a matrix and I do not get the results. GH gives “Null Matrix”.

Change the panel with a slider.

No- Unfortunately it does not work. I am wondering is there anything wrong with my version of GH

Matrix multiplication.gh (9.1 KB)

Thanks. I think it is the version of my grasshopper.