I have recently tried to install a couple of pieces of software from 3rd party repositories, and cannot get them to authenticate when installing. This is on Ubuntu Hardy. I have added the GPG key in both cases, run apt-get update, and in one case the developer responded with an updated key, which still didn't help. It could be either coincidence that the keys are not good (but I don't know enough about how they work to know what could be wrong with them), or there's something wrong at my end.

I do know that the regular out-of-the-box Ubuntu repos work fine (main, multi, uni, backports etc)

The two pieces of software in question are qbittorrent, and liveusb. If someone would be kind enough to try installing these using the repositories and the keys, and tell me if they have the same trouble, I would be very grateful.

Instructions for qbittorrent: http://qbittorrent.sourceforge.net/download.php
Instructions for liveusb: https://launchpad.net/~probono/+archive (probono's key is found here: https://launchpad.net/~probono)

Of course, I could just ignore the authentication warnings, but I thought it was worth taking a moment to see if the problem lies at my end or with the developers and let them know if something's up.

If anyone has any other ideas, please let me know!