I lived the same problem. I wanted to connect to internet via my 6230 bt modem in dial-up networking, but after 1 minute telephone resets itself. Connection lost. I said this problem to my local nokia dealer and they said problem may be occupied from software. i updated version to 4.28 but nothing changed. With data cable, there is no problem. I think there's a bluetooth hardware problem in this phone, because i tried gprs bt connection with another manufacture phone. i saw that there is no problem. Nokia must inspect this problem.