It's a lot easier (and more likely to be useful) when we try to help with a specific problem, error message, or sample of unexpected output. "
I can' (sic) seem to pass it the correct data" doesn't really provide enough info to reply cogently. So perhaps you'll come back to add information about what data you've passed and on what basis you inferred that that data was not "correct."
And, not just BTW, have you exhausted whatever help exists in the doc for Parallel::Iterator/?
If I've misconstrued your question or the logic needed to answer it, I offer my apologies to all those electrons which were inconvenienced by the creation of this post.