Klikerko – it might be backing up the leftover files from failed backups. Check the backwpup directory in the uploads directory.
Mine fails with 3.0.6 too. On one site I have the same symptoms as alanudi – the job log doesn’t pop up when i run the job manually, and no log file is written.
On another site, the job completes successfully but the backup file doesn’t appear on S3 or Dropbox. The job did restart due to inactivity during the upload though.