I also had the dreaded "CD changer not found" problem, so after searching the posts for some answers I went down to see Cleeve Morrison at La Jolla Audio (one heck of a nice guy). I'm not affiliated with them in any way other than close proximity to my workplace, but they're a real class act. After exchanging CD units for a very reasonable price, everything works perfectly. In addition to having many different CD changers in stock, they even give a 1yr guarantee!
Customer service doesn't get any better than this folks!
Kudos Cleeve!
Vince
P.S. Many thanks for taking the time to share your wisdom on this forum.