I just tried a Cesium build under a fresh 64bit Ubuntu 12.04 install. It comes up with some non-intuitive ‘file does not exist’ message on Tools/nodejs-0.6.17/linux/node. To run that 32 bit binary I had to install 32 bit libraries via…
sudo apt-get install ia32-libs
It might be worth adding a note in the contributor’s guide if it’s not already in there, or even better, adding a 64bit node binary into the repo and build config.