Hi There,
Thanks for writing in! After reviewing the information provided above, I would try checking with your hosting provider on this particular issue as it sounds like something related to your setup is causing this. Typically, this is due server configuration problems (i.e. underpowered, traceroute issues, packet loss, permissions errors, et cetera). Additionally, your host will be able to diagnose things much better due to the fact that they have a more complete view of your account and can work behind the scenes with you. If the problem you are experiencing persists after working with your host, don’t hesitate to let us know and we will be happy to assist you. Any relevant information that you can share with us from your host is also greatly appreciated as it will help us to better ascertain the source of the problem.
In the meantime you can download the Cornerstone .zip file here. Extract and upload the cornerstone folder on your server’s /wp-content/plugins directory.
Let us know how it goes, Cheers!