Stanley,
Thank you for your interest and assistance in solving this problem. I did a search in Spotlight for "Extract775D6949-A583#5251AD.aif" and got no finds. However, when going through the entries in my iTunes music library to clean up unwanted songs, I came accross two titles that had bizzare names with "775D6949-A583#5251AD.aif" appended to the ends. These "songs" were not recognizable by title. But when I clicked to play them they were both audio files that I had created several months ago while converting my digital video to DVDs using FCP and DVDSP.
They had never been in my library before as far as I know. Could it be that these titles were somehow created in iTunes when my iTunes library was synched to AppleTV? Or perhaps they were there all along unnoticed until they were "discovered" by AppleTV?
In any event this is what I did: I deleted these files with the long suffix and then followed the suggestion of a poster at Apple Forums and recreated my iTunes library.
The problem resolved. I suspect that recreating my library was not really necessary and just trashing the strangely named audio files was what did the trick.
Anyhow, now I am a happy camper. The message is gone and I can easily switch between AppleTV and my iTunes library as the "Source" for viewing or streaming.
Thanks again for your time and effort.
John
