No, no "use" needed. I wrote my code in a simplistic way so that it didn't "require" or "use" any other modules.

Again, as before, I suggest you compare output with your "reference system". I suspect that something is wrong with @INC and %INC.

I don't know how to "fix" your problem, meaning how to correct the INC paths but other Monks may know. I asked that you compare this system versus the "reference system" that is working and you haven't provided that.