Source update problems

[geek]

I have a problem to update my source!
This is my supfile:

SRCSUPFILE:
*default host=cvsup2.freebsd.org
*default base=/usr
*default prefix=/usr
*default release=cvs tag=RELENG_4
*default delete use-rel-suffix
*default compress
src-all

and my procediment was that:

root# cvsup -g -L2 SRCSUPFILE
root# make buildworld
root# make buildkernel KERNCONF=MYKERNEL
root# make installkernel KERNCONF=MYKERNEL
root# make installworld
root# mergemaster
root# reboot

i do "cvsup -g -L2 SRCSUPFILE" right, but when i make make buildworld the answer was: make: don't know how to make buildworld. Stop!

What can be ?