Code changes not deploying to robot?

[Dinnesy]

My team has deployed the following code to our robot:
package org.usfirst.frc.team4968.robot;

import edu.wpi.first.wpilibj.SampleRobot;
import edu.wpi.first.wpilibj.RobotDrive;
import edu.wpi.first.wpilibj.Joystick;
import edu.wpi.first.wpilibj.Timer;

public class Robot extends SampleRobot
{
RobotDrive myRobot; // class that handles basic drive operations
Joystick leftStick; // set to ID 1 in DriverStation
Joystick rightStick; // set to ID 2 in DriverStation
public Robot()
{
myRobot = new RobotDrive(0, 1);
myRobot.setExpiration(0.1);
leftStick = new Joystick(0);
rightStick = new Joystick(1);
}
public void operatorControl()
{
myRobot.setSafetyEnabled(true);
while (isOperatorControl() && isEnabled())
{
myRobot.arcadeDrive(leftStick);
//myRobot.tankDrive(leftStick, rightStick);
Timer.delay(0.005); // wait for a motor update time
}
}
}

Initially, the code was working. However we then tried redeploying the code with a few changes, and the robot stopped working. So, we reverted the code back to EXACTLY what it was when it was working, and redeployed it, but the robot still does not work. I believe this to because by our code is not successfully deploying to the robot, because no matter what we do, nothing seems to change and the robot does not respond. Could someone outline the code deploying process for us to ensure we are not missing anything? Does the build.xml file need to be updated?