Sorry for the inconvenience. Known Navigation header breakage, its being "rebuilt."
There may be other unforeseen breakage primarily in the handbook portion of the wiki.
The Table Of Contents section of each "PC-BSD® Users Handbook" page may be the best workaround.
Convert a FreeBSD System to PC-BSD®/9.2
Make sure you have these ports installed, using pkg_add or ports:
# svn co svn://svn.pcbsd.org/pcbsd/current current
# cd current/src-sh