Error loading stylesheet:…

I am testing your plugin V3.9.2, wordpress V3.4.2, multi-site.

on my main blog page (staging site), your plugin work great as see here.

on sub-blog it give me Error loading stylesheet: A network error occurred loading an XSLT stylesheet:
as see here please view by firefox

I found post with similar problem here, but it was a year ago with an older version (i guess).

any idea how to fix this? or a way to test and see that it will work before I implement the plugin on my live site?
I want to switch to this plugin, but the live site has pretty height visitor number therefore I really need to make sure that It will work free of error first.

Thank you in advance.

http://wordpress.org/extend/plugins/xml-sitemap-feed/