've just upgraded to sib 6.2 and purchased gpo4. when I try to use the aria player to play/edit a midi file (following the directions in the manual) I don't get anything in the player, the message by the playback slider just says 'empty'. Any guesses as to what i'm doing wrong?
Are you trying to use the MIDI functionality inside Sibelius? It needs to be running in standalone mode for that.
My hunch is that the MIDI file you're using might have its data on a channel other than the slot on which you've loaded an instrument. Try loading an instrument on several different slots or changing the MIDI input on the loaded piano to Omni. Did that make a difference?