The custom event log MyCustomLog is not configured on this system. You will not be able to monitor this event log on this system. The service (agent) will continue to run without interruption.
This message indicates that one or more filters are configured to monitor the "MyCustomLog" event log, but the custom event log is not present on the machine being monitored.
This is an informational message only, informing you that the custom log you configured is not present on the target machine.