Error opening /etc/shadow for reading

[Goran Dobosevic <goran@dobosevic.com>]

Hi,
I'm new to linux and have Debian Lenny for 3 month. Today when i was 
open kde user manager so i can add my self to fuse group I got this 
massages:
Error opening /etc/shadow for reading.
kde user manager was open without root pasword
edit my accaunt->add to fuse group->ok
Can't create backup file for /etc/passwd
Cannot open file /etc/group.bak for writing.
Can't create backup file for /etc/group

Before that I was try to add  my external hd to mount point.
cp /etc/fstab /etc/fstab.bak
pico  /etc/fstab
/dev/sda5       /mnt/external     ntfs-3g    
user,locale=en_US.utf8       0       0
rm /etc/fstab.bak

Can anybody help me?

Thanks in advance,
Goran.

--
Goran Dobosevic
www.dobosevic.com