refer a class from a nested movieclip

I have the class avanzada.as:


package
{

import flash.display.MovieClip;

import pek.difuminar;

public class avanzada extends MovieClip

{

}

}


I use it as document class and basically imports other classes.


I have the class difuminar.as:


package pek{

import flash.display.MovieClip;

import flash.filters.BitmapFilter;

import flash.filters.BitmapFilterQuality;

import flash.filters.BlurFilter;

public class difuminar extends MovieClip
{

public function difuminar(destino)
{

var blur:BlurFilter = new BlurFilter();

blur.blurX = 25;

blur.blurY = 25;

blur.quality = BitmapFilterQuality.LOW;

destino.filters = [blur];

}

}

}



"difuminar.as" blurs a movieclip.


I use apply this class to a movieclip in the main time line with this code:

new difuminar(cuadrox);


"cuadrox" is the name of the movieclip.

It works.

I want to use this class inside a nested movieclip.

I have a movieclip called:

box

Inside this movieclip I have another movieclip called:

gift


How can I use the class "difuminar" to modify "gift" movieclip from box movieclip timeline.


1.

In "box" movieclip timeline I used this code:

new MovieClip(root).difuminar(gift);

but it fails.

Appears this error message:

"1137: Incorrect number of arguments. Expected no more than 0."


2.

In "box" movieclip timeline I used this code:

new MovieClip(this.root).difuminar(gift);

but it fails.

Appears this error message:

"1137: Incorrect number of arguments. Expected no more than 0."



3.

In "box" movieclip timeline I used this code:

new difuminar(gift);

but it fails.

Appears error this error message:

"1180: Call to a possibly undefined method difuminar."



4.

In "box" movieclip timeline I used this code:


import pek.difuminar;

new difuminar(gift);


And it works!

but, it is mandatory to add import pek.difuminar?

or I am doing something wrong?


I attach the files.

Thank you in advance