Why does my CustomTools network client fail to start?

In some cases when installing the client and using a network serial number (beginning in 1084) the user is not prompted to enter the name of the license server.  This leaves the registry entry for it empty, causing the client to fail to start.  Enter the name of the server in this registry key to resolve it:

HKEY_LOCAL_MACHINE\SOFTWARE\ATR Soft\CustomTools\Security\LicenseManager Machine