N-body Simulation - Forces For Body Not Calculating In Some Instances?

I am making a n-body simulation. For some reason, when I have two bodies orbiting each other and I add a third body, the two initial bodies stop orbiting each other.

EXAMPLE:

[URL]- earth is orbiting the sun, when I add mars,[URL] earth AND mars does not orbit the sun and both travel in a straight line. Almost as the forces are not being computed at all on the body. How can this be?

Here is the relevant code:
 
public void update(float deltaTime){
for(int i=0; i<bodies.size();i++){
resetForces(); 
bodies.get(i).update((float)(deltaTime / Math.pow(10,9))*timeScale);
lastTime = System.nanoTime();
//sets the forces for all bodies
for(int n=0; n<bodies.size();n++){

[code]....