Automatic backup doesn't work

[mvtlam]

It says that:

Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1404, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1397, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1277, in main
    globals.archive_dir).set_values()
  File "/usr/lib/python2.7/dist-packages/duplicity/collections.py", line 691, in set_values
    self.get_backup_chains(partials + backend_filename_list)
  File "/usr/lib/python2.7/dist-packages/duplicity/collections.py", line 814, in get_backup_chains
    map(add_to_sets, filename_list)
  File "/usr/lib/python2.7/dist-packages/duplicity/collections.py", line 808, in add_to_sets
    log.Debug(_("File %s is not part of a known set; creating new set") % (filename,))
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 23: ordinal not in range(128)

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: deja-dup 24.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-19.30-generic 3.5.7
Uname: Linux 3.5.0-19-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.6.1-0ubuntu9
Architecture: i386
Date: Thu Dec 6 20:04:12 2012
InstallationDate: Installed on 2012-02-18 (291 days ago)
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
MarkForUpload: True
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
SourcePackage: deja-dup
UpgradeStatus: Upgraded to quantal on 2012-10-21 (46 days ago)