I wouldn't be too quick to blame it on pyTivo. Take one of the longer VOB's, rename it with a .mpg extension and see if it will go back using Tivo-go-back, i.e., not using pyTivo. You could also try it without renaming, just to see what happens. From your debug file I can see that pyTivo is identifying it as tivo-compatible and should be just directly transfering it without transcoding. (Of course it has to be showing on the NPL, and selected for viewing, before this can happen.) Thus I suspect the problem is the TiVo's choking on VOB files. (AFAIK it doesn't say anywhere that VOB's are TiVo-compatible.) This will show during a go-back transfer too. Where were the errors thrown? (Tivo or PC?) Did They occur before you even selected a file from NPL to view?