upgrade from feisty to gutsy update-manager 0.59.24 error: NameError: global name 'os' is not defined

Binary package hint: update-manager

when i run from terminal update manager -d tis is the report:
warning: could not initiate dbus
extracting '/tmp/tmpIXNzh3/gutsy.tar.gz'
authenticate '/tmp/tmpIXNzh3/gutsy.tar.gz' against '/tmp/tmpIXNzh3/gutsy.tar.gz.gpg'
could not send the dbus Inhibit signal: global name 'dbus' is not defined
Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/UpdateManager/UpdateManager.py", line 914, in on_button_dist_upgrade_clicked
    fetcher.run()
  File "/usr/lib/python2.5/site-packages/UpdateManager/Core/DistUpgradeFetcherCore.py", line 178, in run
    self.runDistUpgrader()
  File "/usr/lib/python2.5/site-packages/UpdateManager/DistUpgradeFetcher.py", line 53, in runDistUpgrader
    if os.getuid() != 0:
NameError: global name 'os' is not defined

this is strange, because this bug sems to be fixed from version 0.59.22 of update manager
i tryed these steps:
upgrade and update of the system (feisty)
delete /usr/lib/python2.5/site-packages/UpdateManager/UpdateManager.py
purge update-manager and update-manager-core
reinstall update-manager and update-manager-core
update manager -d
but the output is the exact same

i have xfce-desktop full installed and all the standard repos active