Fixed executeCommand() to now include a conditional clause that determines the existence of the INotification to Command mapping before attempting command execution...
if (isset($this->commandMap[ $note->getName() ]))
{
$commandClassName = $this->commandMap[ $note->getName() ];
$commandClassReflector = new ReflectionClass( $commandClassName );
$commandClassRef = $commandClassReflector->newInstance();
$commandClassRef->execute( $note );
}