I didn't think it was so much "lost" as "rejected". Gabriel Yared was commissioned to write the score originally, but his work was rejected and James Horner's score was then commissioned and used. (While not a common occurence, it's certainly not unheard of). Yared did have the tracks on his official site, but was made to remove them (the producers of the movie still own the rights). You may be able to track it down on the net/P2P - I had a quick Google, without any luck. Don't bother following the link from Filmtracks - it goes to some Christian site.