This means yes, you have there an unnamed function. Make sure you have all event listeners enumerated, and check if you have a listener added like this:
addEventListener(Event.ENTER_FRAME,function():void {...});
Any event can be in place of an enter frame event I wrote. If so, this is the line with an error. An event listener function should always accept 1 parameter of corresponding Event type. In this case, the correct line should be:
addEventListener(Event.ENTER_FRAME,function(e:Event):void {...});
Note the parameter type. If you, for example, listen for a "click" mouse event, it should be of MouseEvent type instead.