Thanks for that info. It helped me determine the actual cause quicker. It appears to have been an ISY failure, perhaps due to a power hit or something. I was able to get in via an alternate Admin access and restore from a backup. It was simply a coincidence that 16A was released just as I had a failure. I would have tried a backup sooner, but I wasn't able to get admin access until I tried the original default. I thought I had disabled it. Your comments pointed me in the right direction.
BTW, thanks for the constructive reply. I was a bit concerned that the newbie "badge of honor" would dissuade assistance. I've actually had the 994 for about 7 years and my automation experience goes back to when X-10 was BSR (early 80's). I just don't post much to forums, but usually debug it on my own. Thanks for the help!