You can try backing up all your files, formatting your card and then copying YSMenu + games + apps back on to your card.
I got that error message a few times after using the latest YSMenu+DSTT1.07a07 at first.
This game works on:
-EzflashV+ (confirmed by a lot of people)
-Acekard2 using AKAIO 1.5 (confirmed by a lot of people)
-Supercard DS One without save (confirmed by 3 guys)
-CycloDS Evolution firmware 1.56 beta 3 (confirmed by a lot of people)