are you sure you didn't upgrade netpkg (with "netpkg upgrade-all/upgrade-new/netpkg").
This problem appears when netpkg is upgraded to the new version without loading the new config file.
If netpkg was updated, you can do :
(and answer "yes" at least on the question about using the new /etc/netpkg.conf)
mv /etc/netpkg.conf.new /etc/netpkg.conf
To solve the problem