обновление ubuntu 8.04

sudo do-release-upgrade
Checking for a new ubuntu release
Done Upgrade tool signature
Done Upgrade tool
Done downloading
authenticate 'precise.tar.gz' against 'precise.tar.gz.gpg'
extracting 'precise.tar.gz'
Traceback (most recent call last):
File "/tmp/tmpKXpYvO/precise", line 3, in <module>
from DistUpgradeMain import main
File "/tmp/tmpKXpYvO/DistUpgradeMain.py", line 25, in <module>
import apt
ImportError: No module named apt

apt-get install python-apt
python-apt is already the newest version.