dispatchEvent undefined

Hi everyone !

for my first message on that forum (which seems to have pretty good users), a little question :

I Have this in a class :

import flash.net.URLRequest;
import flash.net.URLRequestHeader;
import flash.net.URLRequestMethod;
import flash.net.URLLoader;
import flash.net.navigateToURL;
import flash.events.Event;
import flash.utils.ByteArray;
import flash.display.Stage;

    protected function execute_complete(evt:Event)

And flash answers " call to a possibly undefined method dispatchEvent"
I tried to look from which package that function is from… so I import Stage… but it doesn’t work…

Idea ?
thank you !

ps: excuse and correct my English, I’m learning !