I noticed that the kind developers of Hydrogen have posted an update for us at their website. This worked on Jaunty Jackalope for me. Also available are Windows binaries for Hydrogen that work in Vista.
You can install it by downloading from SourceForge using the commands below:
dpkg -i hydrogen_0.9.4rc1_i386.intrepid.deb
Of note, is more use of Qt4 elements with less eye candy on the skins, and questionably easier to interpret. I kind of feel it clashes, but the Instrument and drum kit editor have been combined. It means one less place to find things, and that is progress.