Unity C# global namespace

Im having problems with global name spaces in Unity With C#

I have the following code in two separate files

FILE: MyUtil.cs

using ....
using ....

public class MyUtil :  Photon.PunBehaviour
{
  public static IEnumerator DoStuff(string link)
  {
      WWW sss=new WWW(link);
      yield return sss;
  }
}



FILE: TestClass.cs

using ....
using ....

namespace NewNameSpace {
  public class TestClass : MonoBehaviour
  {
     public void useIt()
     {
       StartCoroutine(global::MyUtil.DoStuff("www.link.com")); <<< error here
     }
  }
}

Im getting error on the StartCoroutine line saying that MyUtil class itself is not found in the global namespace.

I want to call MyUtil.DoStuff from useIt method, but it wont compile.

Anybody knows why?

Thanks