Trying to modify Voronoi Map in D3JS

Trying to modify Voronoi Map in D3JS

I am trying to modify this D3 example to use with my dataset
http://mbostock.github.io/d3/talk/20111116/airports.html
I think my problem is creating the array of coordinates for calculating
the Voronoi polygons, but at this point I'm not sure. I'm getting a
"Uncaught TypeError: Cannot read property '0' of undefined" Error that
points to the line where I am calling the array. The code is live, here
http://cds.library.brown.edu/projects/mapping-genres/symbol-maps/brown-voronoi-map.html
The map displays just fine, but the data points, the radio button, and the
voronoi lines do not appear (I'm not trying to show lines between data
points, so that code has been removed).
Any thoughts or suggestions would be most appreciated. Many thanks!