Hi, Richard --
Ellen is correct about some of the functionality you might find on Wikipedia not working here. We are using an older version of the wiki software, and the functionality you're referring to may not be included in our version, or it may just not be enabled.
However, I make sortable wiki tables all the time by using the class "wikitable sortable."
You just have to make sure that you don't have any stray spaces in your cells when you use that class or you'll get unpredictable sort results.
Here's an example of a sortable table I set up: My Cousin Table, and here are the parameters I used to create it:
{| class="wikitable sortable" border="1" cellpadding="4" width="100%"
Hope that helps!
p.s. In my rush, I neglected to go look at your table before I wrote that. ;-) I see that you're using the "wikitable sortable" class already. I will add, though, that we don't have control over how the wiki markup works in this type of situation.
If you'd like to look at the details of how I have my cousin table set up, let me know, and I'll add you to the trusted list for a bit.