if you use your Nokia 3650 in combination with an OSX Mac you should upgrade to Apple Bluetooth 1.2.1 (and iSync 1.1)
This update includes the latest and most stable Bluetooth drivers for Symbian phones like the Nokia 3650
download from the Apple website :
http://www.apple.com/downloads/macosx/apple/applebluetooth.html
Good Luck !!
Toon.B