From NetBSD FAQ (web site)

"Frequently Asked Hardware Questions

** What does device not configured mean? (top)

  * If this message appears during the autoconfiguration output of system
    boot, it means
    ...
   
  * If this message appears when you try to access a device node in /dev (e.g.
    a SCSI disk), this means that the driver can't find the specific device
    unit you tried to access, e.g.
    ...
"

That's all about "Device not configured".
But there is another case:

% pfctl -f /etc/pf.conf
pfctl: /dev/pf: Device not configured
%

'modload pf.o' help in this case...

-- 
Best regards, Aleksey Cheusov.