I have had several arrangers and sometimes had the same message when moving files from one model to another.
IF ITS A REGISTRATION HERE AND NOT A SONG
I am no expert, but what i do when this happens - is copy all the parts of a reg. individually and save these to user ...ie. the voices and styles. That does help in some cases. I have also maybe had the message 'style file lost' so i find it has to be saved in user.
I usually find a newer model will read an earlier files but sometimes not the reverse.
not sure if the 775 came out before genos
Ironically sent my friend SX regis and they wont play on genos but styles are ok.
Sure you will maybe get a better answer from one of the gurus...but just have a go in the meantime, it might work/help
Keith