I'm trying to run the lego NXT motor from A port using processing. Below is the sample code that i use to try out:

import processing.serial.*;
import pt.citar.diablu.processing.nxt.*;

LegoNXT nxt;
void setup() {
  println(Serial.list());
 
  nxt = new LegoNXT(this,Serial.list()[2]);
}
 
  void draw(){
   
    nxt.motorForward(0,-30);
    delay(1000);
    nxt.motorForward(0,-30);
    delay(1000);
  }

This is the error i received while running:


WARNING:  RXTX Version mismatch
    Jar version = RXTX-2.2pre1
    native lib Version = RXTX-2.2pre2
[0] "COM11"
[1] "COM13"
Exception in thread "Animation Thread" java.lang.ArrayIndexOutOfBoundsException: 2
    at sketch_may24c.setup(sketch_may24c.java:30)
    at processing.core.PApplet.handleDraw(Unknown Source)
    at processing.core.PApplet.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:662)


IS THERE ANY HINT ON CONTROLLING ROBOT NXT USING PROCESSING. JUST THE BASIC THAT HELPS TO CONTROL NXT ROBOT MOVING AROUND USING PROCESSING.