If you're having troubles with the nokia-binaries line, see if it works from a desktop machine. This will rule out any networking issues on the N900*. I had scratchbox setup on my desktop first and just copied the nokia-binaries line from my desktop machine onto my N900.

* I have experienced a problem with apt caused by the phone not getting the same DNS results my desktop got, even though it was connecting through the desktop (USB) at the time. I ended up resolving that by copying lines from my desktop's /etc/resolv.conf into the phone's one.