They are not empty, they are in a sequence, download all the files and then put them in one folder and then extract the first file. That way it will work, if you extract individually they will not get extracted. Extract only the first file part 1 in folder. and use Winrar and not windows default extractor. Zip will take more space and I cannot split the file into so many files of 250 mb, that is why winrar is used.