I was about to answer too. I better just guide you instead. This guy needs to know when You breed Manaphy with Ditto you don't get Manaphy eggs, you get Phione eggs. The Manaphy egg was only for DPPT/HGSS and you get it from the Pokémon Ranger game for the Nintendo DS. The egg itself can only be sent to DPPT/HGSS, nowhere else. Also, to hatch eggs faster, have a Pokémon with flame body in the front of your party and do this:
https://i.ytimg.com/vi/Ib0i_1Nv71Q/maxresdefault.jpg
Also is DPPT supposed to mean Diamond, Pearl, and Platinum? And I think you can trade the Manaphy egg between DPPT and HGSS.