Comment 1 for bug 229327

I get the same error upgrading from 8.10 to 9.04.

~$ sudo do-release-upgrade
Checking for a new ubuntu release
Done Upgrade tool signature
Done Upgrade tool
Done downloading
extracting 'jaunty.tar.gz'
authenticate 'jaunty.tar.gz' against 'jaunty.tar.gz.gpg'
exception from gpg: GnuPG exited non-zero, with code 8323072
Debug information:

gpg: symbol lookup error: /usr/local/lib/libreadline.so.5: undefined symbol: PC

Authentication failed
Authenticating the upgrade failed. There may be a problem with the network or with the server.