package com.medini.events 
{
	import flash.events.Event;

	public class StringEvent extends Event 
	{
		private var _value : String;

		public function StringEvent(value : String, type : String, bubbles : Boolean = false, cancelable : Boolean = false)
		{
			_value = value;
			super(type, bubbles, cancelable);
		}

		public function get value() : String {
			return _value;
		}

		public function set value(value : String) : void {
			_value = value;
		}

		public override function clone() : Event
		{
			return new StringEvent(value, type, bubbles, cancelable);
		}

		public override function toString() : String
		{
			return formatToString("StringEvent", "value", "type", "bubbles", "cancelable");
		}
	}
}

what package structure are you using Ben?

Podium custom event

ActionScript 3