Settings in server?

I have my own server at home (as a hobby project) and is a bit curious how the settings should be on the server for this particular program to work. Right now it does not want to start the backup, I can set up everything and pressing the “Start Backup” but after that nothing happens.

Or if it depends on something else, I do not really know where to look

Hoping for good and clear help 🙂

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