freebsd9-64bit# cd /usr/ports/ports-mgmt/pkg
freebsd9-64bit# make deinstall && make clean && make install
Shared object "libbsdyml.so.0" not found, required by "libpkg.so.0"
===>  Deinstalling for ports-mgmt/pkg
Shared object "libbsdyml.so.0" not found, required by "libpkg.so.0"
===>   pkg not installed, skipping
Shared object "libbsdyml.so.0" not found, required by "libpkg.so.0"
Shared object "libbsdyml.so.0" not found, required by "libpkg.so.0"
===>  Cleaning for pkg-1.0.12_1
Shared object "libbsdyml.so.0" not found, required by "libpkg.so.0"
Shared object "libbsdyml.so.0" not found, required by "libpkg.so.0"
You are about to convert your system to pkgng while you have ports/packages
installed with the old pkg_install tools.
You can choose to: 
- keep pkg_install as the package management system by adding this line to /etc/make.conf:
    WITHOUT_PKGNG=yes
- switch to pkgng:
    1) Add WITHOUT_PKGNG to /etc/make.conf
    2) Install ports-mgmt/pkg
    3) Convert your package database by running pkg2ng
    4) Remove WITHOUT_PKGNG from /etc/make.conf
*** [pre-everything] Error code 1
Stop in /usr/ports/ports-mgmt/pkg.