Lost all saved data due to corrupt data

I don't think you can save the game. But you can try to reset the game.

Unfortunately, once the save data is overwritten, it cannot be recovered.

contact nintendo about it and a receipt shouldnt matter either ok:)

i know how to solve this click on to the suit room and click onto the computer there shud be there if this was no help then just leave a comment

You can try to contact nintendo and tell them your problem. They will most likely send you a new game or try to fix the old one

its auto save

try going to a game store and asking or look in the manual

When on the main menu trey clicking on new game instead of load game and then if a screen appears saying are you sure the you have deleted the previous game save

HERE IS THE WALKTHROUGH

http://www.gamefaqs.com/portable/ds/file/943953/55512

There could be a couple of reasons it's doing this.
If your son has not tried to use a gameshark (a cheating device) then I would take the DS back to the store for a replacement. This is assuming that he bought it new. If it's second-hand then you'll probably have no idea,unless he bought it off of a friend.
If he used a gameshark...that could be the problem.
Gamesharks are used to change data...sometimes they will corrupt the machine up as well...my oldest son went through this with Pokemon. It rendered his machine totally useless for several months...corrupting other games as well. He finally sent the machine in to have it serviced. Another thing that can cause this is connecting it to a computer...the tech said that anytime you connect something to a computer you are at risk for viruses...I had no clue...but he wouldn't lie to us would he? lol
Before running off to service repair,I would try re-setting the info on the DS itself.
Without a game in it,go to the main menu of the DS and try re-entering the date and such. This may help.