We have many customers updating to newer versions of Cablecast that find that older files that have validated in the past are not failing the validation Often time this comes from files that have pulldown settings on them causing the frame-rate to be invalid.
Pulldown/Pullup are methods used to modify the frame-rate of a file. It is most often seen when using film/movie content that has been shot at 24FPS to get the frame rate up to the 29.97 that it needs to be for broadcast. The ratios of pull down are basically telling you at what increment the file has to replay a frame of video to get the frame rate up to 29.97. 2:3 pull down is used to get the frame rate of film based files shot at 24fps up to the 29.97 needed for broadcast.
When dealing with files that have a 29.97 frame rate natively any pull down setting will make the file invalid. So when ripping a file from DVD or transcoding a file with a broadcast frame rate not dropdown or pullup should be used.