Cross domain issues

I'm having trouble setting up a fairly simple site that I want to use FB Connect. Nothing crazy with popups, iframes, etc. At my end, it just has an FB login button on the page. I am getting cross-domain error after following instructions FB tutorial

Error

Permission denied for http://www.facebook.com (document.domain = http://facebook.com ) to get Location.href property from http://localhost:8080

(document.domain not set).

I have an xd_receiver.htm file and I verified that I can navigate to it via the path I set using the Connect url, etc. What's weird is that this works great in Safari but not Firefox. Any ideas? Thanks in advance.