Error building policykit

[Frank]

Does anyone know why I am getting this?

gmake[3]: Entering directory `/usr/ports/sysutils/policykit/work/PolicyKit-0.9/doc/man'
/usr/local/bin/xsltproc -nonet http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl polkit-auth.xml
I/O error : Attempt to load network entity http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
warning: failed to load external entity "http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"
cannot parse http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
gmake[3]: *** [polkit-auth.1] Error 4
gmake[3]: Leaving directory `/usr/ports/sysutils/policykit/work/PolicyKit-0.9/doc/man'
gmake[2]: *** [all-recursive] Error 1
gmake[2]: Leaving directory `/usr/ports/sysutils/policykit/work/PolicyKit-0.9/doc'
gmake[1]: *** [all-recursive] Error 1
gmake[1]: Leaving directory `/usr/ports/sysutils/policykit/work/PolicyKit-0.9'
gmake: *** [all] Error 2
*** Error code 2

Stop in /usr/ports/sysutils/policykit.
** Command failed [exit code 1]: /usr/bin/script -qa /tmp/portupgrade20090221-17122-1p4epto-0 env UPGRADE_TOOL=portupgrade UPGRADE_PORT=policykit-0.9_2 UPGRADE_PORT_VER=0.9_2 make
** Fix the problem and try again.
--->  Skipping 'x11-servers/xorg-server' (xorg-server-1.5.3_4,1) because a 
requisite package 'policykit-0.9_2' (sysutils/policykit) failed (specify -k to force)
** Listing the failed packages (-:ignored / *:skipped / !:failed)
         ! sysutils/policykit (policykit-0.9_2)  (unknown build error)
         * x11-servers/xorg-server (xorg-server-1.5.3_4,1)


--
Frank