[Arduino] Serialport not open

[yub0309]

i use arduino & node-red and
error message was broke out.

Welcome to Node-RED

5 Sep 13:51:45 - [red] Version: 0.8.1
5 Sep 13:51:45 - [red] Loading palette nodes
js-bson: Failed to load c++ bson extension, using pure JS version
5 Sep 13:51:46 - ------------------------------------------
5 Sep 13:51:46 - [red] Failed to register 1 node type
5 Sep 13:51:46 - [red] Run with -v for details
5 Sep 13:51:46 - ------------------------------------------
5 Sep 13:51:46 - [red] Server now running at http://127.0.0.1:1880/
5 Sep 13:51:46 - [red] Loading flows : ardu.json
5 Sep 13:51:46 - [red] Starting flows
5 Sep 13:51:46 - [log] [inject:tick] repeat = 500
5 Sep 13:51:59 - [red] Stopping flows
5 Sep 13:51:59 - [log] [inject:tick] inject: repeat stopped
5 Sep 13:51:59 - [red] Starting flows
5 Sep 13:51:59 - [log] [inject:tick] repeat = 500
5 Sep 13:51:59 - [log] [arduino-board:2b3d7067.ab8f5] port closed
5 Sep 13:51:59 - [red] Uncaught Exception:
5 Sep 13:51:59 - Error: Serialport not open.
at SerialPortFactory.SerialPort.write (/home/yuby/node-red-0.8.1/node_modules/arduino-firmata/node_modules/serialport/serialport.js:202:17)
at ArduinoFirmata.module.exports.ArduinoFirmata.write (/home/yuby/node-red-0.8.1/node_modules/arduino-firmata/lib/arduino-firmata.js:165:30)
at null. (/home/yuby/node-red-0.8.1/node_modules/arduino-firmata/lib/arduino-firmata.js:131:24)
at wrapper as _onTimeout
at Timer.listOnTimeout as ontimeout

How can i solve this problem?