Too many users of serial number xxxxxxxxxxxxx. your serial number is licensed for only one user and is already in use on two other computers. This list below may help identify where the other copies are being used."
So using a single package across multiple machines may not be the solution.
Version 9 managed licence info through the registry, but 11 handles it in a file.
You can run the install from their msi on a machine, then on first run enter the licence key. A file was created in All Users\Application Data\Extensis called .SW110. It's in a garbled format, but if you add this file to your installation (I created a transform), then you should be set.