Connecting Nokia 6303 to iMac via Bluetooth

I have an iMac 27" on Snow Leopard and have recently bought a Nokia 6303 phone. I have managed to pair them and each recognises the other, but when I try to connect them the iMac Bluetooth connection flashes a green dot and 'connected' for about a second and then reverts to a red dot and 'not connected'. The Nokia comes up with the message "Service not supported by the other device". I've checked the Nokia's Bluetooth which seems to be ok and the wireless mouse and keyboard work with the iMac. I also have a Time Capsule connected to an Internet router by Ethernet cable and the router is wireless.
The only slight difference seems to be that the Nokia only has space for part of the Mac's bluetooth name and I am reluctant to shorten this on the Mac for fear of losing the mouse and keyboard connections. I suspect I have incorrect Bluetooth settings but don't know how to change them without messing up the bits that work. Can anyone help, please?