make buildworld problem

[Dan Ross]

I am trying to build a new kernel with smp.  I started with make clean 
and got no errors.
I then type make buildworld from /usr/src directory
it runs for about an hour then I get:
gzip -cn /usr/src/sbin/ip6fw/ip6fw.8 > ip6fw.8.gz
===> sbin/ipf
make: don't know how to make bsd.README. Stop
*** Error code 2

Stop in /usr/src/sbin.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
comm1#
suggestions?