The file should not be blank. This issue isn't really PowerCMS related since its just with the transferring of the file itself and before you are even running the installation wizard. I would use another FTP program and see if the upload succeeds. You should also have a web based way to upload the file using the bluehost control panel.
My only guess as to why the file is blanked out is something to do with the FTP program you are using to upload.