This is a simple d3.js tree diagram that loads an external data file as used as an example in the book D3 Tips and Tricks.
It is derived from the Mike Bostock Collapsible tree example but it is a VERY cut down version without the ability to update (collapse).
I would suggest that you make your JSON file as small as possible so that you can confirm that the problem is either in the JSON or the javascript. Then (assuming that the JSON is the problem) slowly add things somponents to the JSON file untill you strike the part of it that is causing the problem.