I made a much simpler project, but have been unable to get it to produce the error, even after running for upwards of 36 hours. I'm seeing if I can reproduce this in my more complex app. There is always the possibility that changes to the DockKit code in later iPhone OS versions have fixed the problem. If I can't my original (complicated) app to error out in a few more days of testing, I'll have to conclude that's what happened. I'll follow up again in a few more days.