If you've reflashed, reinstalled and nobody else is having this issue, but you are, then I'm still inclined to believe that the SD card may be the weak link.

The reason I say this is because I've used two different microSD cards on my Nintendo DS; both functioned just fine for basic stuff like storing files and neither showed any corruption, but only one card would crash my DS if I ever tried to save a game. That taught me that not all cards are built to the same standard of quality.

If you could try a different card, I would recommend this just to be sure that it's not your card.