Can you be more specific on what the original file uses as codec (MPEG-2) and container (.vob, .avi, .mpg, ...) and what settings you used in Toast and Handbrake?
in toast and handbrake i used the standard apple tv settings.
i used streamclip now with apples mpeg2 codec to convert it to mov.
that worked for me now, but still strange why i couldnt convert it in handbrake in the first place.