In the logs, something similar can be found.
DEBUG 2015-01-29T12:30:44  - Replay.Core.Implementation.Licensing.LicenseService () Failed to send heartbeat of the Core to License Portal. LP response: At least one Agent Heart-Beat failed: Value cannot be null or empty.
Parameter name: displayName
WARN 2015-01-29T12:30:44  - Replay.Core.Implementation.Licensing.LicenseService () Last contact with License Portal failed with message: FailedCoreHeartbeat
This is due to the display name key having a null value.
Windows Registry Disclaimer:
Quest does not provide support for problems that arise from improper modification of the registry. The Windows registry contains information critical to your computer and applications. Make sure you back up the registry before modifying it. For more information on the Windows Registry Editor and how to back up and restore it, refer to Microsoft Article ID 256986 “Description of the Microsoft Windows registry” at Microsoft Support.