[Plugin: WordPress Backup to Dropbox] FTP Backup problems

Hi: I am using your plugin but oddly there are numerous backups going to my server (hostgator) and they keep causing over the limit disk space issues. They have indicated it is because of the plugin but this does not make sense to me since the backups go to drop box not the server. Is this true? Am I missing something? Thank you in advance for your help.

http://wordpress.org/extend/plugins/wordpress-backup-to-dropbox/