S Lafredo> I created a file called '/etc/networks/ifconfig.de0' containing the
S Lafredo> line

S Lafredo>  54.13.16.201 netmask 255.255.255.0 media 10BaseT

S Lafredo>  - sent to no buffer space available.

I my experience, I got the very much simliar symptom. In my note,
it says I was missing the word 'inet' in ifconfig file. Say,
        54.13.16.201 netmask 255.255.255.0 media 10BaseT
should be
   inet 54.13.16.201 netmask 255.255.255.0 media 10BaseT

But the machine I am using now does not have the word inet.

makoto@u 9:38:40/011102(~)> cat /etc/ifconfig.gm0 
210.145.40.123 netmask 0xfffffff0 media autoselect

So this may not help at all, sorry.
---
(Makoto Fujiwara)
http://www.ki.nu/software/NetBSD/iBook2/