Flash Builder beta2 Module error

programming flash
1

I use Flash Builder 4 beta 2. I downloaded it from this link http://labs.adobe.com/technologies/flashbuilder4/ and i have a simple example that gives me an error. I am trying to load a module in my application and (of course) interact with the objects that i just loaded. So this is my app:

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/halo" >

    <mx:ModuleLoader url="katana.swf" width="100%" height="100%" />

</s:Application>

and this is my katana.mxml file in src folder (though Eclipse says it’s in src/(default package) )

<?xml version="1.0" encoding="utf-8"?>
<mx:Module xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/halo"    >
    <mx:ColorPicker />
</mx:Module>

The project is compiled successfully and i can run it using Ctrl + F11 and i can see the color picker but when i click it (to select a color) i get this error:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
    at mx.managers::PopUpManagerImpl/addPopUp()[E:\dev\gumbo_beta2\frameworks\projects\framework\src\mx\managers\PopUpManagerImpl.as:417]
    at mx.managers::PopUpManager$/addPopUp()[E:\dev\gumbo_beta2\frameworks\projects\framework\src\mx\managers\PopUpManager.as:184]
    at mx.controls::ColorPicker/http://www.adobe.com/2006/flex/mx/internal::displayDropdown()[E:\dev\gumbo_beta2\frameworks\projects\framework\src\mx\controls\ColorPicker.as:1388]
    at mx.controls::ColorPicker/downArrowButton_buttonDownHandler()[E:\dev\gumbo_beta2\frameworks\projects\framework\src\mx\controls\ColorPicker.as:1715]
    at flash.events::EventDispatcher/dispatchEventFunction()
    at flash.events::EventDispatcher/dispatchEvent()
    at mx.core::UIComponent/dispatchEvent()[E:\dev\gumbo_beta2\frameworks\projects\framework\src\mx\core\UIComponent.as:11749]
    at mx.controls::Button/http://www.adobe.com/2006/flex/mx/internal::buttonPressed()[E:\dev\gumbo_beta2\frameworks\projects\framework\src\mx\controls\Button.as:2769]
    at mx.controls::Button/mouseDownHandler()[E:\dev\gumbo_beta2\frameworks\projects\framework\src\mx\controls\Button.as:3030]

By the way, i am using flash player 10,0,2,54.

What do you think? Am i doing something wrong? or is this a bug in the SDK?