Yesterday I just noticed that on Ubuntu Precise, with a stock Puppet installation (2.7.13), 'puppet module' (a tool to build and install modules) was not available. Soon found an explanation on superuser: 'puppet module' was released with 2.7.14.
There is a straightforward way to get out of this: upgrade Puppet as recommended by PuppetLabs and go straight to version 3 (unless of course you have constraints to stay on 2).
These steps will allow you to get Puppet directly from PuppetLabs repos (just choose the target distribution).
At the moment of writing this procedure would upgrade Puppet on Ubuntu Precise from '2.7.11-1ubuntu2.7' to '3.7.3-1puppetlabs1'.