The powder and the grains are completely different.
I have only used the one from Body Ecology and it has always worked fine for me. I like how I can make 42 batches b/c you can keep dividing it up to 7x. But the grains last forever! I also get a different taste from them which proves the point that you are get a better range of organisms from the live grains.
Maybe your Yogourmet packet wasn't stored correctly and the little buggers were killed off by heat.