To register FileLocator Network enter the registration details in the Registration Code dialog, accessed by clicking on the 'Registration Code...' button in the FileLocator Network About Dialog.
Alternatively simply save the regkey.xml file attached to the registration email, or downloaded from the MyAccount section of the Mythicsoft web site, to the root of the FileLocator Network installation folder, e.g. C:\Program Files\Mythicsoft\FileLocator Network.