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Charlie,
From your above images, I noted that the song being opened was Frontier.mp3 found in \bb\Tutorials - 2007. (Fred took this screen shot from the PG Music tutorial.)
When I tried opening that particular file, or the Frontier.wma file, I got the below error. This error seems to suggest that there is a file called INPUT.TXT that is also required for ACW.

The good news is that when I navigated to another directory and opened a different WAV, the ACW opened fine.
I've reported this error to Support.
Regards,
Noel
P.S. It seems that I can now no longer open any mp3s in ACW