That's because said disc is Blu-ray, the music is in MP3 which PS3 won't read, and you might not have a Blu-ray PC drive. Thus, you're boned.
Not to worry because BioWare have a solution in hand for you, providing you don't mind downloading the collector’s edition bonus content over the EA Downloader on PC. Yes, sorry, the solution to the PS3 issue is to get your composed swag on PC instead.
If you want the soundtrack, you poor PS3 gamer, then contact help.dragonage.com, a BioWare representative told Kotaku. "Our customer service department is ready to help and will ensure that this is resolved," they said. Some users wouldn't agree with that.