I've been using a Motorola bluetooth ear piece and I accidentally chose "No" after checking the "Don't ask again..." checkbox. Now I can't connect to the device.
You should be able to remove and then re-pair the device by going, from the Home screen, to Options, and then to BlueTooth.
And when you pair it to your Blackberry, make sure that it is listed as "trusted". Then, whenever your bluetooth headset is on and near the blackberry, it will automatically accept the connection.
The device does not show up as a paired device so I can't delete it. Every time I try to connect the headset to the phone the "Enter password" screen pops up and then quickly disappears before I can type 0000.