Problem getting colour to change on a text mesh using code

The following code works fine when I am changing colour using <Renderer>().material.color but fails to work when i change it to <TextMesh>. I am trying to get text to change colour on a sprite. These are not UI elements but just standard sprites with a TextMesh attached.

Code (CSharp):

1. {
2.     public Color col;
3.     private Color startColor;
4.     private Color currentColor;
5.     private float blendValue;
6.     private int mouseover;
7.  
8.     void Start()
9.     {
10.         startColor = transform.GetComponent<TextMesh>().color;
11.     }
12.  
13.     void Update()
14.     {
15.         if (blendValue > 0 && mouseover == 0)
16.         {
17.             blendValue -= Time.deltaTime * 0.5f;
18.             transform.GetComponent<TextMesh> ().color = Color.Lerp (startColor, currentColor, blendValue);
19.         }
20.     }
21.  
22.     void OnMouseOver()
23.     {
24.         if (mouseover == 0) {
25.             currentColor = transform.GetComponent<TextMesh> ().color;
26.             blendValue = 0;
27.         }
28.         mouseover = 1;
29.  
30.         if (blendValue < 1)
31.         {
32.             blendValue += Time.deltaTime * 0.5f;
33.             currentColor = transform.GetComponent<TextMesh> ().color = Color.Lerp (currentColor, col, blendValue);
34.         }
35.     }
36.  
37.     void OnMouseExit()
38.         {
39.             if (mouseover == 1)
40.             {
41.                 currentColor = transform.GetComponent<TextMesh>().color;
42.             }
43.  
44.             mouseover = 0;
45.             blendValue = 1;
46.         }
47. }

 

It has something to do with the text mesh object being a child of the GUI parent. When i seperate the Text as a stand alone object the text works fine. But making it a child again the colour change stops working. But why? There is nothing odd about my GUI parent:

 

Ok! I have debugged further, the problem lies in the RIGIDBODY. When i remove the rigidbody the lerp works. Whu would a rigid body be affecting this code??