i have just installed a Chimpmate plugin and an error message displays on admin panel when you go to the plugin configuration and you can not subscribe on homepage at martingearjewellers.ie:
(http://martingearjewellers.clisr.com/wp-content/plugins/chimpmate/src/google_fonts.json) [function.file-get-contents]: failed to open stream: HTTP request failed! HTTP/1.1 403 Forbidden in /home/clisrcom/public_html/wp-content/plugins/chimpmate/admin/class-chimpmate-wpmc-assistant-admin.php on line 333
i use the same plugin on different wordpress installation with the same plugins and theme but without your wpmu dev dashboard and it works correctly.
i have just granted support access, can you have a look?