FWIW, you don't seem to be alone:
http://forums.attwireless.com/attws/...essage.id=3633
(unless that IS you...)
4) After using the headset in my car, if I put the headset back on the charging cradel or turned it off and went somewhere, when I next recieved a call the phone would begin to ring but then immediately cut off displaying a message: "Internal Bluetooth Error (212)". This caused me to miss several calls..