NullReferenceException with GetComponent

[cloudsyk3]

My code is as follows:

1. gameObject.GetComponent<UISlider>().value = 0.00f;
2.                 Debug.Log ("loading value = " + gameObject.GetComponent<UISlider>().value);

and console log is:
NullReferenceException: Object reference not set to an instance of an object
loading value = 0

It is strange that it says null ref but could print out, the script is set in the gameobject.

Thanks

[Caio.Lib]

Hi,

When you click on the message in the console is the same GameObject?
Are you using more than one script for this GameObject?

I think the error comes from another script.