$.getJSON not working in IE8

$.getJSON not working in IE8

Hi

This is related to a bug ticket I opened. Probably shouldn't have opened it as a bug because I'm still not sure.
http://dev.jquery.com/ticket/6750

I'm building a Facebook game that runs in an iFrame. When I use 1.4.2 it works on FF, Chrome and Opera but creates a problem with $.getJSON in IE (I have only tested on IE 8). The error it returns is "Object doesn't support this property or method" on the statement return new A.XMLHttpRequest

The problem disappears if I switch to v1.3.2.

I tried to upload HTML, JS and CSS files so people debugging wouldn't have to go to the Facebook app, but it's not getting correctly replicated. So unfortunately you will have to look at the app to analyze :(

For now it's not a showstopper for me because it works on 1.3.2 but I figured I'd raise it here and get enlightened.