This External Exception is usually a sign that you are having network connectivity issues. It has also been caused by having a workstation running Windows XP SP2 attached to the network.

This is not an Adagio issue. You can type the error message into Google and see the circumstances under which it can occur.

To begin with, I would unplug and reattach every cable between each workstation and the server to make sure the connections are well seated. (Not while anyone is in Adagio of course!)