javascript failure only on subdomain

I’ve created my own plugin that calls a jquery ajax function that returns some json data, which is then inserted into div.

Now, everything works on all of my pages throughout the site, so long as the url is:

http://www.mountmadonnaschool.org/values/

however, we setup a redirect to the above URL from:

http://values.mountmadonnaschool.org/

However, when the plugin tries to initiate the ajax function- nothing appears to happen. When trying to execute an ajax function using Firebug in the browser, it told me ‘XMLHttpReadystate=1 multipart=false’. And that’s as far as I could get with it.

To get around this, I’ve just written a piece of javascript to change the browser url to the one that works, but that’s not the ideal solution. Can anyone give me any clues?