streamMessage command dosn't work

There is following exception:

Exception in thread "main" java.lang.NullPointerException
        at pl.nask.hsn2.unicorn.connector.ConnectorImpl.receive(ConnectorImpl.java:119)
        at pl.nask.hsn2.unicorn.commands.StreamMessagesCommand.execute(StreamMessagesCommand.java:33)
        at pl.nask.hsn2.unicorn.Unicorn.main(Unicorn.java:42)