[GeometriX_ZA]

After struggling with this plugin, then the installation of Wowhead tooltips (BCMath was showing up as disabled even though it's enabled on my server), I decided to poke around at other options and found a surprisingly simple solution that requires no plugins or files to upload:

Grab the code to run the Wowhead's own script from here: http://www.wowhead.com/tooltips. Paste it into your header includes file.
Then create a new BBCode item like this: <a href="http://www.wowhead.com/item={option}">{param}</a>

I hope someone else can put this to use and save themselves the time it took me to figure this all out.