Foglight Agent Manager error: "Unable to establish loopback connection" (4240821)

When starting the Foglight Agent Manager (FglAM), the following errors are found in the logs:

2015-02-03 14:53:27.291 ECHO    WARN [Startup Thread] com.quest.glue.core.util.CommonsLoggingToQuestBridge - failed org.mortbay.jetty.nio.SelectChannelConnector$1@380c709c: java.io.IOException: Unable to establish loopback connection

2015-02-03 14:53:27.292 ECHO    WARN [Startup Thread] com.quest.glue.core.util.CommonsLoggingToQuestBridge - failed SelectChannelConnector@127.0.0.1:0: java.io.IOException: Unable to establish loopback connection

2015-02-03 14:53:27.292 ECHO    WARN [Startup Thread] com.quest.glue.core.util.CommonsLoggingToQuestBridge - failed Server@6b944d61: java.io.IOException: Unable to establish loopback connection

2015-02-03 14:53:27.292 WARN    [Startup Thread] com.quest.glue.core.comms.transport.DownstreamManager - Cannot start downstream HTTP server

java.io.IOException: Unable to establish loopback connection

This failure causes the FglAM master to not be able to initialize its downstream connection that listens for Out-of-Process (OOP) deployments (e.g. .NET agents).