Can't move GUI

I'm trying to get a GUI health bar in my 2-player game. After reading through many similar questions on this site, I still can't find a way to resolve this issue.

I was looking on the Unity GUI Scripting Guide to find how to make a health bar, and it gives this code:

     var bgImage : Texture2D; // background image that is 256 x 32
     var fgImage : Texture2D; // foreground image that is 256 x 32
     var playerEnergy = 1.0; // a float between 0.0 and 1.0
     function OnGUI () {
 // Create one Group to contain both images
 // Adjust the first 2 coordinates to place it somewhere else on-screen
 GUI.BeginGroup (Rect (0,0,256,32));

 // Draw the background image
 GUI.Box (Rect (0,0,256,32), bgImage);

 // Create a second Group which will be clipped
 // We want to clip the image and not scale it, which is why we need the second Group
 GUI.BeginGroup (Rect (0,0,playerEnergy * 256, 32));

 // Draw the foreground image
 GUI.Box (Rect (0,0,256,32), fgImage);

 // End both Groups
 GUI.EndGroup ();
 GUI.EndGroup ();
 }

I'm assuming this works just fine if it were singleplayer, but that is not what I want. So since I have splitscreen, I thought I should make 2, and move one of them to the other side of the screen. This doesn't work, as whenever I try to move it, the box just splits the background and foreground and/or stretches all over the place and doesn't work (see image)

This is the code I wrote that i thought would let me be able to adjust its' position:

 var bgi : Texture2D;
 var fgi : Texture2D;
 var hitCounterCheck : int;
 var otherScript : TankScript;
 var otherObject : GameObject;
 var posW : int;
 var posH : int;
 
 function Awake (){
 
 otherObject = gameObject.Find("Player 1");
 otherScript = otherObject.GetComponent(TankScript);
 
 }
 function Update () {
 hitCounterCheck = otherScript.hitCounter;
 }

 function OnGUI(){
 
 GUI.BeginGroup (Rect (posW,posH,posW+256,posH+20));
 GUI.Box (Rect (posW,posH,posW+256,posH+20), bgi);
 GUI.EndGroup();
 GUI.BeginGroup (Rect (posW,posH,hitCounterCheck * 51+posW,posH+20));
 GUI.Box (Rect (posW,posH,posW+256,posH+20), fgi);
 GUI.EndGroup();
 
 }

But that just causes the image below, where the first group stays at 0,0, and refuses to move. How can I get them both to move where I need?