SongbookPro is designed to function perfectly on Chromebooks. Unfortunately, the latest update has broken functionality such that the latest version will fail to open when installed on any device with an Intel processor (ie most chromebooks).
We are working towards a fix for this but in the mean time, please follow the following procedure to instal the previous working version of SongbookPro.
Ensure SongbookPro is uninstalled from your device (create a backup of your songs if possible first).
Enable ‘Installing apps from Unknown sources’ by following these tutorials:
Download the version of SongbookPro found here and install the app file