Sparks #5-6 were never released as individual comics (the trade paperback indexed as “Sparks (Sideshow Productions)” contains all six issues).
You can read the interview with the creator.
“ Sparks was originally a comic book. Only four out of the six issues came out in June 2008. We accidentally missed getting into PREVIEWS for issue 5, and even with an emergency email sent to retailers, we didn’t get enough orders to print issue 5.”
I recommend deleting #5-6.