Failure to finish installing PHP for LAMP

[velikij]

When I try to build and install PHP when trying to install LAMP (according to how_to_install_a_lamp_server on the netbsd wiki), I get the following failure message:

===> Install binary package of libxml2-2.8.0nb2
pkg_add: A different version of libxml2-2.8.0nb2 is already installed: libxml2-2.7.8nb10
pkg_add: 1 package addition failed
*** Error code 1

I can't delete the old libxml2 since it is required by various other installed packages such as openbox, various xfce4 packages, etc.

Some system info:

System running on bsd.xxx:
NetBSD 5.1.2 i386
NetBSD 5.1.2 (GENERIC) #0: Thu Feb 2 17:22:10 UTC 2012 builds@b6.netbsd.org:/home/builds/ab/netbsd-5-1-2-RELEASE/i386/201202021012Z-obj/home/builds/ab/netbsd-5-1-2-RELEASE/src/sys/arch/i386/compile/GENERIC
model name : Intel(R) Celeron(R) CPU 1.70GHz
MemTotal: 2016380 kB
MemFree: 1585288 kB

My pkgsrc-supfile looks like
*default tag=.
*default release=cvs
*default delete use-rel-suffix
*default umask=002
*default host=cvsup.us.netbsd.org
*default base=/home/peter

netbsd-pkgsrc

My .xinitrc file is set to run openbox right now, though I have xfce4 installed.

Are my pkgscrc sources out of sync with packages that I formerly installed as binaries, such as the whole X system, openbox, xfce4, etc?

- Peter