When your Camera(s) finish, do you have the expected number of images that match your frame count in EIAS? If so, then I suspect the conversion process. My method is to open up the rendered .img's in Quicktime Pro as an image sequence and convert from there- usually to a Quicktime movie, animation codec, lossless with alpha, which AE can read just find. Set the frame rate to 25fps in Quicktime Pro Player, then re-interpret in AE if you need to.
Hope this helps.