how to convert a object to boolean

It sais everytime in the console:''Cannot convert ‘boolean’ to ‘Unity.Monoscript’ ‘’
Does someone have a solution?

Code:

var OptionsLevel : String;
var GraphcicsScript : Monoscript = false;

function OnMouseEnter (){
    renderer.material.color = Color.black;
}

function OnMouseExit (){
    renderer.material.color = Color.white;
}

function OnMouseDown (){
if(GraphcicsScript){
GraphcicsScript = true;
} else {
Application.LoadLevel(OptionsLevel)}
}

Not sure I understand the question. Here is your code with my comments:

var OptionsLevel : String;
var GraphcicsScript : Monoscript = false;   // MonoScript??? if you need to load a script into this variable, dont set it to false, set it to null.

function OnMouseEnter ()
{
    renderer.material.color = Color.black;
}

function OnMouseExit ()
{
    renderer.material.color = Color.white;
}

function OnMouseDown ()
{
   if(GraphcicsScript)  // this is only true if the variable is a boolean and the value is true
   {
        GraphcicsScript = true; // so why set it to true again?
   } else 
   {
      Application.LoadLevel(OptionsLevel)
   }
}

My guess is that you are trying to check if a certain script is loaded or not?

I think you might want to check this link first:

http://unity3d.com/support/documentation/ScriptReference/ScriptableObject.html