Edge DS

I am not sure if this is a problem with my flash cart or just my DS.I was playing my DS earlier today, around 7:10 A.M. I had to go somewhere, so I put it in my pocket. I didn't play it for about 5 hours, and when I played it, the game played fine, music played, the game worked. Then, the game loaded and the screen went black,(Sands of Destruction, when it goes to a new scene) the music kept playing, but the screen stood black. Was this from my Edge card or just my DS?

Is the firmware the most recent?I'd say it's A.P (anti-piracy) blocking it, different games work differently depending on the AP side of things.

yes, my Edge has the highest FW.It could be AP, but I never heard of AP working that way.
Maybe it was because my DS was pushing against me and the pocket, putting pressure on it?