modify / extend PanoSalado.as

Hi,

First of all thank you guy for your great job !
Secondly, please excuse-me for being new in panorams, flex, AS3... but I want to learn and anderstand how to modify it !

I played this xml settings file and samples ; everything was ok. Now, I want to integrate the player in an existant project (movieClip in fact) and, whichis important modify different things as interactivity way, cursors, etc... I just want to modify the code !

I opened PanoSalado.fla, xxx.as, ModuleLoader.fla, xxx.as ; change lines but when I want to test the ModuleLoader animation, the compiler returns this error

Error #2044: IOErrorEvent non pris en charge : text=Error #2035: L'URL est introuvable.
Error #2044: IOErrorEvent non pris en charge : text=Error #2035: L'URL est introuvable.
TypeError: Error #1007: Tentative d'instanciation sur un élément non constructeur.
at Cursor()

The strange thing is that it generate a new swf that runs in the standalone flash player without using my changes !

Here is my question :
what is the best way to modidy PanoSalado ?
should I or extend it ?
do I have to use Flex ?
Do you have a link or a document that helps me ?

Thanx in advance !