For those that may stumble across this thread in the future:

Not all versions of the program have a Data folder with an Installers folder inside of it, so in such a case you can install the fonts by re-running the Band-in-a-Box program installer and making sure your fonts are checked.

Font files may no longer be found on your computer if you copied/moved Band-in-a-Box from one machine to another, installed an upgrade without first installing the previous full version, or system security software running on your computer (such as an anti-virus or firewall program) prevented the fonts from being installed properly. This is also common if you just plugged in an external hard drive version of Band-in-a-Box, without running the setup file.

Cheers,
Ember