Microsoft Knowledge Base Article 887443 describes the following symptoms:
When you view the System log in Event Viewer on a Microsoft Windows 2000 Server-based computer that is running the Terminal Services Licensing service, you see events that are similar to the following:
Event Source: TermServLicensing
Event Category: None
Event ID: 17
Description: One or more Terminal Services Licensing certificates on server Server_Name are corrupt. Terminal Services Licensing will only issue temporary licenses until the server is reactivated. See Terminal Services Licensing help topic for more information.