These instructions are not valid anymore since January 2011, since the majority of the ETP machines is running Ubuntu 10.04 now.
The Atlas software is typically available for Scientific Linux systems. To be able to use Athena, DQ2, etc on an Ubuntu machine, using a Scientific Linux Atlas release, do the following before setting up the Athena / DQ2 environment:
Then run your regular Atlas or DQ2 setup.
This sets the PATH and LD_LIBRARY_PATH such that you get the correct gcc version (4.3.2) and the libraries needed by Athena / DQ2 / etc.
Tested with 15.6.6 and 15.6.10, from the local kit installation, and with DQ2 0.1.35 from AFS, on Ubuntu 9.10 (karmic). Not guaranteed to work with everything that Athena can do.