It seems you need the original game CDs to get the music on OpenRA. Incidentally, I have both the original 3 1/2" disk and the remastered CDs from the early 2000s -- but no computers with CDs or floppy drives. I'm willing to even purchase the music a third time, but seems OpenRA wants a CD -- has anyone gotten around this?
I just installed openRA and it says you can use an installation or cd. Maybe you could find an installation online and use your unlock key?
Does it play the music via Redbook audio? I wonder if you could "burn" mp3s to a virtual audio CD and then mount it.