Your example of pie chart remote data binding works great when the web service is hosted in the same place as the HTML, but it seems to be erratic if the web service is hosted somewhere else.
What I did was create a WCF service that returns a JSON object exactly like your example web service, and then call it with your exact HTML.
Reproducing the error is simple: take the pie chart remote data binding example
and change the web service address so it's hosted in a domain different to the HTML. Obviously, you need to change to JSONP and add the callback function.