Hi I'm new with ROS  ,as I want to test the NXT, I did the complete installation and as I'm using the Bluetooth dongle recommended by Lego with my laptop (Ubuntu) but I cannot connect I got an error 
[ERROR] 2010-09-02 22:03:50,429: [Errno 111] Connection refused
Unable to register with master node [http://localhost:11311]: master may not be running yet. Will keep trying.
[INFO] 2010-09-02 22:04:52,563: signal_shutdown [signal-2]
[WARNING] 2010-09-02 22:04:52,565: cannot unregister with master due to network issues
[INFO] 2010-09-02 22:04:52,565: signal-2
[INFO] 2010-09-02 22:04:52,674: connected to core topic /rosout
[ERROR] 2010-09-02 22:04:52,736: Unable to initialize /clock: [Errno 111] Connection refused


but not sure how to fix this issue, 

please any help will be appreciated


Thanks