Sorry for the inconvenience. Known Navigation header breakage, its being "rebuilt" but forward nav should be ok now.
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.
Translations:Installing Applications and Keeping Up/9.2/12/en
It also describes how to Create Your Own PBI Repository of custom PBIs.