sudo add-apt-repository ppa:gwendal-lebihan-dev/cinnamon-stable
[sudo] password for gantry:
You are about to add the following PPA to your system:
 Cinnamon stable
 This PPA contains the stable releases of cinnamon for oneiric.

Cinnamon website : http://cinnamon.linuxmint.com/
 More info: https://launchpad.net/~gwendal-lebihan-dev/+archive/cinnamon-stable
Press [ENTER] to continue or ctrl-c to cancel adding it

Traceback (most recent call last):
  File "/usr/bin/add-apt-repository", line 99, in <module>
    sp = SoftwareProperties(options=options)
  File "/usr/lib/python2.7/dist-packages/softwareproperties/SoftwareProperties.py", line 96, in __init__
    self.reload_sourceslist()
  File "/usr/lib/python2.7/dist-packages/softwareproperties/SoftwareProperties.py", line 580, in reload_sourceslist
    self.distro.get_sources(self.sourceslist)
  File "/usr/lib/python2.7/dist-packages/aptsources/distro.py", line 91, in get_sources
    raise NoDistroTemplateException("Error: could not find a "
aptsources.distro.NoDistroTemplateException: Error: could not find a distribution template