From what I can tell this bug is definitely about network-admin. It seems that gnome-nettool is calling network-admin to configure the interface, but with superuser credentials (gksu), which no longer works in Ubuntu 8.04 since network-admin requires you to use the 'unlock' button. If I run 'gksu network-admin' from the command line, I get the same error (on standard error at the command line, not the GUI error dialog) about looking up session information that I get when I click on the 'configure' button in gnome-nettool.
Jan:
From what I can tell this bug is definitely about network-admin. It seems that gnome-nettool is calling network-admin to configure the interface, but with superuser credentials (gksu), which no longer works in Ubuntu 8.04 since network-admin requires you to use the 'unlock' button. If I run 'gksu network-admin' from the command line, I get the same error (on standard error at the command line, not the GUI error dialog) about looking up session information that I get when I click on the 'configure' button in gnome-nettool.