Are you sure 13.04 didn't have packages before? I did a fresh install of 13.04 last week, added the Ubuntu PPA, and installed the Bitcoin packages. Today, I got the notification that some packages needed upgrading. After "apt-get dist-upgrade", the packages bitcoin-qt, bitcoind, and libdb4.8++ were upgraded. After the upgrade, bitcoin-qt/bitcoind no longer start due the error I mentioned.
Ahh, this is your problem...yes, raring had no packages whatsoever in the PPA, so when you installed bitcoin-qt, you actually installed Ubuntu's version, which depends on libdb5.1, making your wallet incompatible with bitcoin.org's binary releases. Raring currently has the latest 0.8.1, however Ubuntu is not likely to keep that up to date as new releases come out. If you have a backup of your wallet prior to the upgrade (I'd hope so) and you haven't done anything with it since, you can just restore that backup and use the PPA versions. Otherwise you will have to either continue using Ubuntu's version (remove the ppa, remove bitcoin packages, reinstall, and hope you dont fall too far out of date) or build your own bitcoin-qt/d and keep doing so using libdb5.1.