D3.js json error when making tree
===

I am trying to make my own tree in D3.js, but I am having trouble figuring out how to make one.  I have looked at the following links:

http://bl.ocks.org/1249394#interactive_tree.css <br>
http://stackoverflow.com/questions/11137238/d3js-tree-square

and even tried copying them to get something working so that I can tinker, but it won't work for me.  I have riddled the code with alerts and in both the pedigree and the collapsible tree the code stops working right after the d3.json call.  I copied the json files too and renamed them so that they were the same. In the pedigree example 


    d3.json("info.json", function(json) {
      alert('hi');
      var nodes = tree.nodes(json);	
      alert('hi');

So here the first alert works and the second doesn't, and this happens in both examples. If anybody knows why, an explanation or fix would be greatly appreciated. Thanks!!!
