I've had an almost similar problem with Pairing my ThinkOutside Stowaway keyboard a few months back. Could be something buggy in N900's Bluetooth manager. I ended up using the python simple-agent script (I think it was the one mentioned at http://wiki.openmoko.org/wiki/Manual...ooth#Pairing_2) I don't think I made any changes, and you can, of course, find the file in lots of other places, e.g. towards the end of http://developer.toradex.com/knowled...-use-bluetooth Worth a try.
Nokia-N900:~# ./simple-agent hci0 C2:3A:79:20:0A:76 Creating device failed: org.bluez.Error.ConnectionAttemptFailed: Page Timeout