Comment 1 for bug 230832

I am having the same problem using apt-cacher-ng, when trying to upgrade to Ubuntu 8.10 I get the following:

magicfab@andrea:~$ sudo do-release-upgrade
Checking for a new ubuntu release
Failed Upgrade tool signature
Done Upgrade tool
Done downloading
extracting 'intrepid.tar.gz'
authenticate 'intrepid.tar.gz' against 'intrepid.tar.gz.gpg'
exception from gpg: GnuPG exited non-zero, with code 131072
Debug information:

gpg: WARNING: unsafe permissions on homedir `/tmp/tmp-AFwaU'

gpg: can't open `/tmp/tmp-AFwaU/intrepid.tar.gz.gpg'
gpg: verify signatures failed: file open error

Authentication failed
Authenticating the upgrade failed. There may be a problem with the network or with the server.
magicfab@andrea:~$