It sounds like he is saying that some of the cells were fragmented. That is totally normal. You should call and ask for a clearer explanation but any RE who is ethical would not transfer embryos that were not healthy. As for outcomes, many many women get pregnant with less than perfect embryos and since you put three back you have a great chance!!! Good luck.
The wall of the blastocyst should thin down and open at some stage to get iimplanted. He could have meant that they have disintegrated to get implanted which could mean a good thing.
Keep positive.