Can't build with references from one script to another

Hi,

I’m referencing two scripts from my main script in this fashion;

public class MouseLook : MonoBehaviour {

//

CreateBlueBall lol;
MeshCSGOperation meshCSGOperation;

void Start()
{
        meshCSGOperation = GameObject.FindObjectOfType(typeof(MeshCSGOperation)) as MeshCSGOperation;
        lol = GameObject.FindObjectOfType(typeof(CreateBlueBall)) as CreateBlueBall;
}

The code runs in the editor and I can call methods from these scripts, however when I build the scripts to debug them I get the error: “The type or namespace ‘CreateBlueBall’ could not be found (are you missing a using directive or an assembly reference?)”.

I don’t know why this is happening as it works in the editor?
Any help would be appreciated, thanks.

Can you show the script “CreateBlueBall” ?
In which folder it is?