I just purchased 5 EventSentry licenses, but I am not able to add the 5th computer to a group. I can add 4 computers just fine, but I cannot add the 5th one. Why not?

The default installation of EventSentry includes a "Heartbeat" group that includes the host www.myeventlog.com for illustration purposes. This host does use up one license, which is why you can only add 4 licenses.

You can either delete this host from the group (right-click host and select delete) or delete the entire group by right-clicking it and selecting Delete Group.