OK, I've built on salutis's earlier work and prepared an updated thinkingrock .deb package for tr 2.2.1. I've passed it to the Ubuntu REVU process, but in the meantime it's in the Ubuntu PPA area so it's easy to pick up.
If you're running karmic (Ubuntu 9.10), just paste this at a command-line:
sudo add-apt-repository ppa:crazyscot/tr && sudo apt-get update && sudo apt-get install thinkingrock
Earlier versions than 9.10 should also just work, but it's slightly more involved. If you know to edit your sources.list file, add the following line to it:
deb http://ppa.launchpad.net/crazyscot/tr/ubuntu karmic main
Otherwise, go into the Software Sources control panel, Third Party Software tab, click on Add and paste in the line above. Either way, you should then be able to install it:
sudo apt-get update && sudo apt-get install thinkingrock
The package is marked for the karmic release (Ubuntu 9.10) but because it's all-java, it should just work on any recent Ubuntu provided you can satisfy the dependencies. Indeed, it also seems to work on the debian lenny (5.0) box I had to hand.
I've passed the package to the Ubuntu REVU process to see if it can be adopted into the archive; if it is, that build will supersede this one.
Caveat: I think the packaging works, and there doesn't seem to be anything glaring wrong, but please do report a bug (ideally via Launchpad) if anything is wrong with it.