From: DeskNow Knowledge Base
http://www.desknow.com/kb/

java.io.IOException: Unable to establish loopback connection
http://www.desknow.com/kb/idx/6/115/article/

This means that the OS on which you installed DeskNow does not support Java's native I/O API.

Simply edit the Messenger.cfg configuration file and set the following line:

PlainConnector.NIO FALSE

then restart DeskNow