"Do I need to download V3 again since my version is probably old and that's why the decoding doesn't work?"

From what I recall DAZ issued at least three different versions of V3 over the years: V3, V3 Sr1 and V3 SAE.

I decoded against the blMilWom_v3.obj file that came with V3 SAE, the newest version of V3.

You also made sure to use blMilWom_v3.obj and not blMilWom_v3.obz ?