A .dmg file is the OS X native disc image file format. It might work if you try mounting the .dmg image using your favorite burning app. I don't use windows so I don't know all the programs. Maybe Nero or Roxio? I know I can mount most any disc image format in OS X natively and using Toast (OS X), like dmg, img, iso, bin, cue, whatever. Give it a try.

But, you might not want to bother. The MUX.dmg file is just a bunch of mp3's (I was curious so I checked). I'm sure those SW covers have been gone for a long time.