Button Sound, What is going on?

I am not sure what I am missing. I have a background sound that plays when player enters level. I then want the player to simply hit a button to hear a quick sound. I have applied the background sound to the camera and it plays. I have a button that shows up in the top left corner of the screen. When hit it is suppose to play "darkSwish". I have dropped script from the project onto the game object and the audio clip from the project screen onto the darkswish Script. I do get an error stating "There is no 'AudioSource' attached to the "GameObject" but a script is tryint to access it" I have turned off the 3D sound on both the background sound and the darkSwish. Here is the GUI script I have for the Dark Swish button. Please what am I doing wrong

var darkSwish : AudioClip;

function OnGUI() { if(GUI.Button(Rect(0, 0, 200, 100), "Dark Swish")) { audio.PlayOneShot(darkSwish); } }

Select the gameobject with Audio Script attached and go to Components>Audio>Audio Source then apply the darkSwish sound to the newly attached Audio Source Component. Now it should work.