Dear Cloudbase9,
While I have no experience in a Mac environment and therefore can't really help you with the error, I can at least verify that you are not seeing things.
Adagio.exe is indeed an executable file that was shipped with the Adagio CDs. I believe that's the file that the Auto Play function would run to get things started.
I think that because we are all so used to dealing with the Download versions of the install files that this slipped Andrew.
Regards, Pete