I ran into the same problem being discussed on this thread, and looked through the images (on-camera) for a video file. I didn't find one, but I did find a single image that appeared to be corrupted. To resolve the problem in my case, I deleted that single file (again, from the camera's on-board image viewer).
I suspect that the problem here isn't just limited to video files (or at all related to 10.6.4 video drivers). Rather, I suspect the issue is just that iPhoto's import module bails at the first sign of an image that it can't decode. Given that the same problem seemed to occur in Image Capture, I suspect that module is part of a common library used by both applications.