ubuntu problem

[GOvvin]

I'm on ubuntu 4.1 preview. It's been running fine for a few weeks now
but now I have a problem: i can't configure my Network Settings. A
popup will display "The configuration cannot be loaded. There was an
error running the backend script."

Prior to this, I think I unchecked samba/windows networking from
network settings. I believe that's the last thing I did before I
encountered the error above. How can I rectify this?

thanks in advance.

PS
I'm lookning at the system log viewer. the last entry says:
sudo (pam_unix) authentication failure; logname= uid= euid= tty=
ruser= rhost= user=myname
/usr/bin/sudo erwin'TTY=unknown' PWD=/ User=root; COMMAND=/usr/bin/network-admin
su + pts/0 root':root
(pam_unix) session opened for user root by (uid=0)

PPS
i'm new to linux. ;-)