How do i get snapshot to request dropbox authorisation?

Hi,
I cant seem to get snapshot to talk to dropbox to configure it. I have created a drop box account. In the snapshot settings do I just enter a location in the dropbox destination field? Wen I do this and press save destination I just get a blank screen. This is in my browser nav http://www.kawebhosting.co.uk/wp-admin/network/admin.php?page=snapshots_destinations_panel&snapshot-action=add&type=dropbox

Any ideas of what I may be doing wrong? Thankyou.
Karen