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.
Using Brasero in GNOME
Brasero is an easy to use CD-ROM/DVD burner included with the GNOME desktop. To launch Brasero, click Applications -> Sound & Video -> Brasero Disk Burner:
The dialog window shown in Figure X-XX will be displayed. If you click on Burn image -> Click here to select a disk image, you will be able to select your .iso file. Once selected, click "Open". The next window, seen in Figure X-XX, allows you to select your CD-ROM drive, as well as a few other options. Leave these options as default. Click "Start" and Brasero will begin to burn your DVD: