how to lock a cursor

i am using the screen.lockcursor script to try and make the mouse disappear during gameplay but it doesn't work and says 'The scripts file name does not match the name of the class defined in the script!' wnat does this mean and where do i put a script like this when it is fixed. thanx for any help.

here is the script

// Called when the cursor is actually being locked

function DidLockCursor () {
Debug.Log("Locking cursor");

// Disable the button
guiTexture.enabled = false;

// Called when the cursor is being unlocked
// or by a script calling Screen.lockCursor = false;
function DidUnlockCursor () {
Debug.Log("Unlocking cursor");

// Show the button again
guiTexture.enabled = true;

function OnMouseDown () {
// Lock the cursor
Screen.lockCursor = true;

private var wasLocked = false;

function Update () {
// In standalone player we have to provide our own key
// input for unlocking the cursor
if (Input.GetKeyDown ("escape"))
Screen.lockCursor = false;

// Did we lose cursor locking?
// eg. because the user pressed escape
// or because he switched to another application
// or because some script set Screen.lockCursor = false;
if (!Screen.lockCursor && wasLocked) {
wasLocked = false;
// Did we gain cursor locking?
else if (Screen.lockCursor && !wasLocked) {
wasLocked = true;
DidLockCursor ();

When you added a script, are you sure you chose Create -> JavaScript from the Project menu?

Adding a C# script and not having the class name the same as your script object name will give you that error.