In order for two (or more) Bluetooth devices to be able to work together to accomplish a given task, such as file sharing, they need to both support the appropriate profiles. The Bluetooth SIG has defined countless profiles, such as Headset, A2DP Stereo, OBEX File Exchange, to name just a few. This is why devices such as Bluetooth keyboards are generally not usable with mobile phones - most mobile phones do not support the necessary HID Bluetooth profile.
Research In Motion
A2DP