Looks like Andrew was replying around the same time I was before. You can either install just sforzando from the Data\Installers folder that he had advised, or re-install the main Band-in-a-Box program. Either way should get it back. If you are going from the Install Manager, you need to select your Band-in-a-Box name on the left hand side, below the enter Download URL button. Then click on the button beside the Band-in-a-Box and RealBand listing to start the download of just that file. Once it is downloaded it will automatically open the Setup wizard and when you click Next on this window you'll eventually get to a similar screen as what I had previously posted.

Best,
Chantelle