Update icon doesn't allow guest users update by clicking on it (quits without message)

[thatsallurspaceships]

LMDE 201108 RC Gnome
Left clicking the update icon in taskbar. After entering password nothing happens. The Update Launcher GUI should appear and check for updates. Instead this application runs from Gnome-Menu System->MintUpdate after entering root password as user without root. This happens everytime with user that is not root. The main user however can use the taskbar icon by entering password.

[Gwendal LE BIHAN (gwendal-lebihan-dev)]

Is your user in the sudoers file ? What administrative permission does he have ?

[thatsallurspaceships (csub)]

etc/sudoers
Defaults env_reset
root ALL=(ALL:ALL) ALL
the rest is marked off
The user is a desctop-user without manually edited permissions.

[thatsallurspaceships (csub)]

After adding the user to group-ID 1001 there is the notification "/usr/lib/linuxmint/mintUpdate/mintUpdate.py 'show' konnte nicht als Anwender root ausgeführt werden:

 The underlying authorization mechanism (sudo) does not allow you to run this program. Contact the system administrator."
This seems to be a user fault by myself. Without assigning a user to a group there appears nothing.

[Launchpad Janitor (janitor)]

[Expired for Linux Mint because there has been no activity for 60 days.]