do-release-upgrade as user 1000

user@ubuntuserver:~$ cat /etc/issue
Ubuntu 10.10 \n \l
user@ubuntuserver:~$ do-release-upgrade
Checking for a new ubuntu release
Get:1 Upgrade tool signature [198B]
Get:2 Upgrade tool [1303kB]
Fetched 1304kB in 0s (0B/s)
authenticate 'natty.tar.gz' against 'natty.tar.gz.gpg'
extracting 'natty.tar.gz'
[screen is terminating]
user@ubuntuserver:~$ cat /etc/gshadow
cat: /etc/gshadow: Permission denied