Lenny-upgrade Synaptic problem

Hello all,

I've just upgraded my system and when I'm trying to setup repositories in synaptic I don't see "repo
window", but I just get window "repositories changed".

I'm getting this output in terminal:

64studio:/home/mira# /usr/lib/python2.5/site-packages/apt/__init__.py:18: FutureWarning: apt
API not stable yet
  warnings.warn("apt API not stable yet", FutureWarning)
Traceback (most recent call last):
  File "/usr/bin/software-properties-gtk", line 100, in <module>
    app = SoftwarePropertiesGtk(datadir=data_dir, options=options, file=file)
  File "/var/lib/python-support/python2.5/softwareproperties/gtk/SoftwarePropertiesGtk.py",
line 75, in __init__
    SoftwareProperties.__init__(self, options=options, datadir=datadir)
  File "/var/lib/python-support/python2.5/softwareproperties/SoftwareProperties.py", line 55, in __init__
    self.reload_sourceslist()
  File "/var/lib/python-support/python2.5/softwareproperties/SoftwareProperties.py", line 450,
in reload_sourceslist
    self.distro.get_sources(self.sourceslist)    
  File "/usr/lib/python2.5/site-packages/aptsources/distro.py", line 85, in get_sources
    "Error: could not find a distribution template")
aptsources.distro.NoDistroTemplateException

Thanks for any advice.

mirami