PNGIO error

I've been experiencing a problem with my Blender renders for a bit now with After Effects. I get a PNGIO error and AE crashes. When I investigate the error message and go to the frame in the render sequence where AE crashed I find a bad frame. So I rerender that frame. Sometimes I go back to a project and it happens again, or it happens when I'm pretty positive that my render is clean. So I'm convinced at this point that Blenders not spitting out bad frames but AE is going to interpret them, gets confused, then rewrites a bad frame over it. Can anyone else speak to this? I see in an earlier thread that many of you are using PNGs. Anyone else having this problem? Thanks for the help,
~Chris