huh, that’s really weird. I’ve done the save editor for the US version of the game, and the Japanese version. I’ve also done it with my Wii and my Wii U with no issues. Something may be up. Hopefully you have a backup of your save before you used the save editor.
Are you using a physical memory card or an SD to hold your saves?
I’d basically just go in and replace the broken save file with the backup of the one before you used the save editor, make sure everything is alright and then backup again, use the save editor and see if it worked.