Checking if file exists

// Here is the general layout of functions used for loading data. Note: You will need to read up on this a bit in order to see how the various functions such as MCLiListener.onLoadProgress is called.

// The event loader that will listen for events
var MCLiListener:Object = new Object();
var MCLi:MovieClipLoader = new MovieClipLoader();
MCLi.addListener(MCLiListener);

MCLiListener.onLoadProgress = function(param_target, param_bytesLoaded, param_bytesTotal) {...}

MCLiListener.onLoadComplete = function(param_mc:MovieClip) {...}

MCLiListener.onLoadInit = function(param_mc:MovieClip) {...}

MCLiListener.onLoadStart = function(param_mc:MovieClip) {...}

MCLiListener.onLoadError = function(param_mc:MovieClip, e:String) {...}

// container_mc is the variable reference to some already existing MovieClip that is on the stage.
MCLi.loadClip("FilePath", container_mc);

I dont fully understand this. Where do i insert the URL i need to check?

I trimmed down some code but it is such a small window to edit in.