Permission denied to call XMLHttpRequest.open

That error usually triggers when trying to load via XMLHTTP from a domain different to the current one.
That's prohibited ... unless you do a lot of messing around.

That error is usually triggered accidentally because you or your site is using a site.name and www.site.name interchangably, and doesn't really know what its domain is. They are different hostnames, and not allowed to swap data with each other.

See th readme (or the .htaccess I think) for the fix to this.