Some additional info which might be very relevent when considering my problem getting the orbiter running.
It is installed on a Windows XP laptop which is normally logged into a domain and it's configured for this. I can't change this unfortunately. If this is the causeand it can't be worked around, this isn't a problem for me as long as I know about it.
I ran nmblookup a few times from another machine:
$ nmblookup DCEROUTER
querying DCEROUTER on 10.10.10.255
name_query failed to find name DCEROUTER
$ nmblookup -A <ip_of_dcerouter> -W PLUTO
Looking up status of <ip_of_dcerouter>
LEVIATHAN <00> - B <ACTIVE>
LEVIATHAN <03> - B <ACTIVE>
LEVIATHAN <20> - B <ACTIVE>
..__MSBROWSE__. <01> - <GROUP> B <ACTIVE>
PLUTO <00> - <GROUP> B <ACTIVE>
PLUTO <1d> - B <ACTIVE>
PLUTO <1e> - <GROUP> B <ACTIVE>
MAC Address = 00-00-00-00-00-00
BTW "Leviathan" is the hostname of the box that plutohome is running on.