I have a communication problem with proccesing and arduino

when I try to run the basic program in Arduino library with proccesing I get this error:

Display 0 does not exist, using the default display instead.

WARNING:  RXTX Version mismatch

                Jar version = RXTX-2.2pre1

                native lib Version = RXTX-2.2pre2

this is the program

import processing.serial.*;
import cc.arduino.*;

Arduino arduino;
int ledPin = 13;

void setup()
{
  //println(Arduino.list());
  arduino = new Arduino(this, Arduino.list()[0], 57600);
  arduino.pinMode(ledPin, Arduino.OUTPUT);
}

void draw()
{
  arduino.digitalWrite(ledPin, Arduino.HIGH);
  delay(1000);
  arduino.digitalWrite(ledPin, Arduino.LOW);
  delay(1000);
}