Project structure, finding scripts vis GetComponent and related errors

I'm not sure how to ask, but I found something a little strange. To explain, I have a camera I'm just trying to switch between my own custom MouseLook script, and the provided MouseOrbit script given in Standard assets. I simply do this to activate/deactivate Mouse Orbit:

   //sample of enabling/disabling attached scripts
   MouseOrbit myScript = GameObject.Find("Main Camera").GetComponent("MouseOrbit") as MouseOrbit;
   myScript.enabled = !myScript.enabled;

My question is, why does the above work fine if MouseOrbit is in the "Standard Assests\Scripts\Camera Scripts" folder, but not if its in my "Scripts" folder?

The error I get is:

  error CS0246: The type or namespace name `MouseOrbit' could not be found. Are you missing a using directive or an assembly reference?