While I haven't integrated pro maps in Wordpress myself, I don't see why it wouldn't work correctly. When I view your example site about, I get a Javascript error in the simplestats.js file. Since there is an error, that is preventing the other JS from running including the stuff for pro maps.
I would recommend using Firebug (its an extension for Firefox) to debug your Javascript and fix any errors. Once you fix the errors, I think pro maps should work. You might want to try just creating a new page in Wordpress to give a clean starting point, and see if the map works on that page. Then add in your other code and see what if anything is causing a conflict.
I also noticed the google_javascript files weren't found on the sample page still.
-justin
