These commands were required to successfully install less.js on a fresh Ubuntu (14.04) server. The bolded symbolic link creation took me an hour to debug. Adding this to the installation documentation could save installers additional hours hunting StackOverflow.

sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install nodejs
sudo ln -s /usr/bin/nodejs /usr/bin/node
sudo apt-get install npm
sudo npm install -g less