Really appreciate your efforts, archiver. With your files, the music is so dynamic that you really have to listen hard, but the 24-96 file definitely has the noise (again, playing from the Toast window, not QT or iTunes), which is carried through to a burned disc. The 16-44.1 file has no noise. Arrrrr!
Now I know that it's not something weird that's happening with Digital Performer when I create my 24-96 files. So thanks for helping me rule that out.