I've had my N900 less than a week and I'm unbelievably impressed with it.

I've been trying to get the Bluetooth tethering working with Ubuntu using the instructions here, but it's giving me an error message after connecting to the phone, which states:
I've tried searching Google for the exact text and similar variations, but have come up empty-handed.
Can anyone give me any pointers? I'm happy to make changes using the terminal if someone provides step-by-step guidance.

FWIW, I'm on Vodafone UK and am typing this on the N900, so I know I have internet access enabled. The Bluetooth connection appears to be sound, as I've been using it for file transfer between the devices.