The Aria player does not appear to be able to find the sound files (which you've probably guessed already). 

On a copy of the file, try using MIDI/Audio > Reassign Playback Sounds and see what happens. 

The instrument sound files for the latest version of Finale are in

See if they are still there in your system. If they are, something has broken the link, and you may have to reinstall Finale--or a tleast the Garritan part of it.

(It would be nice if you would put your version of Finale and your computer Operating System in the info box of your profile, accessed via the pull-down under your name in the stripe at the top of the screen. That would make it much easier to help you specifically.)

I'm having a similar issue with Finale 2014.5. It's not recognizing the GIF Samples

Not knowing anything about your system, all one can do is guess. Do you need to update the Aria Engine? Reinstall GIFF? Did you move your library without rerunning the installer so the paths are set properly?