Q:

how to load text file into flash using AS3?

How to load text file into flash using AS3 . and the text file not on the root but on my server on the internet

A:

There are already a few posts about this. 
Here are 2 examples: Flash AS3 Read Text File
and Working with txt file on as3
What part, specifically, are you stuck on?
UPDATE:
var url:String = "http://concept-vs.com/load/my_text_file.txt";
var loader:URLLoader = new URLLoader(new URLRequest(url));
loader.addEventListener(Event.COMPLETE, onFileLoaded);
function onFileLoaded(e:Event):void
{
    var loader:URLLoader = e.target as URLLoader;
    var text:String = loader.data; // variable text now holds the text from the file
}

