On Pokemon Ranger, can u get Manaphy twice if u type in the code again?

Answer 1

no, because you do not get manaphy - you get a special egg that won't hatch in the game

you then need to transfer that to d/p and you can only receive it once, since it's tagged [unseen probably] by the user id it came from, and duplicates won't work

Answer 2

No. You can only recieve 1 egg per save file on Pokemon Diamond and Pearl, and you can only transfer one Manaphy Egg per Pokemon Ranger card. Annoying, isn't it? Now I can't give my friends Manaphy! Just Fione!