Error Message is as follows:

Failed to load mods: Error while loading item prototype "deadlock-stack-artillery-shell" {item}: Stack size can't be zero.
Modifications: Deadlock Stacking for Vanilla > Deadlock Experimental Stacking

I am placing it here only due to the fact that it is flagging BOTH mods.
(edit: The game disables both mods, not just one or the other.)

I can confirm that Stacking for Vanilla does load completely fine, as does the Stacking Recipes Mod.

Can you give me a save file and a copy of your "mod-settings.dat" ?