Trying to burn a CD: "hdiutil: imageinfo failed - image not recognized"
The Image File created by Burn.app is a RAW Image and does not contain a recognizable filesystem that OS X understands and why hdiutil fails. It's also why an "Audio CD.isoInfo" file needs to be created, so the Burn.app can burn the image it created back to optical media (CD).

Since you created the Audio CD Image with the Burn.app then why don't you just use the Burn.app to burn the Audio CD Image to optical media (CD)?