Ubuntu One won't synchronize files

[NancyG]

When I want to synchronise a file with Ubuntu one, there is no way to do it. If I click on Synchronize this folder, nothing happens.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: nautilus 1:2.32.2.1-0ubuntu13
ProcVersionSignature: Ubuntu 2.6.38-10.46-generic-pae 2.6.38.7
Uname: Linux 2.6.38-10-generic-pae i686
Architecture: i386
Date: Sun Jul 17 00:21:22 2011
ExecutablePath: /usr/bin/nautilus
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: nautilus
UpgradeStatus: Upgraded to natty on 2011-05-05 (72 days ago)
XsessionErrors: (nautilus-sendto:2064): libebook-WARNING **: e-book.c:3095: cannot get book from factory: Invalid source