I was having a similar problem. Rooted, changed device name via Amazon and had both Yahoo and GMail apps installed. I had been experiencing loss of the bar for about an hour and was trying to check my Yahoo acct and noticed Yahoo checked for new mail, but no mail ever populated. No change after reboot. I then uninstalled Yahoo and immediately got the “Talk has stopped“ error, then the bar came right back. The name on the Kindle simply reads “My Kindle“ as opposed to the registered name or the name I changed it to. Thus, while the nature of the error may remain unknown, there is additional support for a communication error and a fairly easy remedy.