Error Compiling Buildworld when upgrading from 5 to 6

[Warren]

Im trying to upgrade my 5.4-STABLE FreeBSD machine to 6 via CVS and have 
problems compiling Buildworld.

Any help/pointers to ways to do the upgrade i may be missing are most welcome.
-----------------------------------------------------------------------------


===> sbin/ipf/libipf (obj)
/usr/obj/usr/src/sbin/ipf/libipf created for /usr/src/sbin/ipf/libipf
===> sbin/ipf/ipf (obj)
mkdir: /usr/obj/usr/src/sbin/ipf/ipf: File exists
*** Error code 1

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

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

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.

-- 
Yours Sincerely
Shinjii
http://www.shinji.nq.nu