Run the SkillSoft Content Installer Kit (CIK) to install the necessary "source" files for the MSI generation. It is recommended that you perform a Custom Installation this can choose to install all the necessary files, all players supported locales and all the SkillSoft supported locales.
The instructions for running the CIK are available here.
Note: The CIK is normally used for installing content to a Web Server, however for generating the MSI a web server is not required. The files can alternately be installed to a local folder on the user's machine.