I just tried obex from my suse11 laptop to n800.
firstly, I paired the n800 to laptop.

then using the kde obex client (kde seems far superior to gnome for bluetooth), it wouldn't transfer from laptop to n800

I then used n800 file manager, picked an image, tapped/hold and sent it using bluetooth to the laptop, and it worked fine!

I then retried from laptop to n800 and it worked no problem, so I think it's a matter of the bluetooth obex servers getting in sync and trusting each other.

good luck!