Thanks. As I suspected Sonar can't really do what I want it to do.
The limited documentation we got with the Organ doesn't state what MIDI is required, just "MIDI". No on line user documentation is available other than what we have. The date on the documentation is 2002. There were some "home made" floppies with MIDI music files on them that came with the organ. These will play in Windows with the Windows Media Player.
Both the BIAB program and RealTracks program are PG Music products. Not sure what the difference is in saving, but BIAB MIDI won't play in the Organ but RealTracks will. I can take the same BIAB song, load it in BIAB and play it OK. If I save as MIDI file, Windows Media Player will play it but it won't play in the Organ. If I take the same BIAB song and load it in RealTracks and save as MIDI both the Windows Media Player and the Organ will play it. I suspect something I'm not setting properly in BIAB? Obviously I can always use RealTracks, but the BIAB has more options for instruments and modifications and I would rather use that if I can come up with what is wrong.
You are correct on format (haven't fully investigated that yet as I'm waiting on a PCIe USB 2.0 port card to use with the floppy drive which is USB 2.0 only (all I have are USB 3.0 and 3.1 ports on my new DAW PC) so I can use my DAW desktop computer instead of a laptop). If I format with Windows on the Laptop, the floppy drive won't recognize the disc, but if I format it with the floppy drive in the Organ Windows 10 recognizes it and I can read and write to the disc. Been years since I used a floppy drive so I have to reorient myself.