Hiya, at what part of the game does this occur?
If you could share any more information that'd be good, thank you ^^
So I try to save at the first opportunity after the intro because I didn't want to have to sit though a lengthy intro twice, and that was just after being prompted to get Kiki dressed (so I hadn't even gone outside yet). It was at that point it threw the error.
I re-started with a NEW GAME (because CONTINUE would throw the error as well). This time I waited till after I had gone outside and after I had gotten Kiki's companion before I tried to SAVE, and it worked fine, no error.
I hope this helps.