Sorry to hear that, Hisserdude. Yes, they could have eaten each other. I've experienced that with some of my D. granti and D. tityus larvae. It's my fault because I didn't notice some of the eggs had hatched and the larvae had run out of food in the small containers I had them in. So, naturally, they ate the eggs that hadn't hatched and any smaller larvae.
So, I'm guessing your rotting wood isn't providing the proper nutrition for your larvae. I seem to recall suggesting live trees for them so they could munch on the roots.
That's all I can think of that would have triggered the cannibalism response.
Cheers