Jenne just discovered an issue with the python-matplotlib package that I knew was coming but forgot about.
We pull packages from the LSCSOFT Debian "squeeze" archive, which is a convenient way for us to install LIGO data analysis software. There are no LSCSOFT archives for Ubuntu, and Debian "squeeze" is the closest supported distribution to Ubuntu 10.04 "lucid", which is what we are using.
DASWG recently added python-matplotlib to the LSCSOFT squeeze archive. The version they added (1.0.1-3) supersedes the version in lucid, so by default apt wants to install it. However, the LSCSOFT version is compiled against a newer version of some standard libraries, so it won't function on our system and seg faults.
The solution (a solution) is to use apt "pinning" to pin the package to the lucid version that works. I've added the following file on all the 10.04 workstations to prevent the package from upgrading to the LSCSOFT version:
controls@pianosa:~ 0$ cat /etc/apt/preferences.d/pin_python-matplotlib
Pin: release a=lucid