You cannot store the database on an SD card - I don't allow it. It causes way too many potential issues that could corrupt the library or cause other failures. If your storage location is on an SD card, the database will be stored under /storage/emulated/0/Android/data/com.zubersoft.mobilesheetspro/files. If you are just trying to have your song files stored on the SD card, you can go to Settings->Storage and tap "Set the MobileSheets Storage Location". Tap the SD card icon to use the OS-assigned folder or pick your own. The library will then be moved over to that SD card location.
Mike
Mike