Cannot Mask Over MovieClip with AS3

programming flash
1

Hello,

I have problem in masking over a movie clip by using ActionScript 3. The masking do not work. Here’s the codes:

effect_mc.cacheAsBitmap = true;
mask_mc.cacheAsBitmap = true;

// Apply Mask
effect_mc.mask = mask_mc;

I upload the flash file to:
http://www.sendspace.com/file/7g35eb

Could somebody help to check why the masking do not work.

Thanks

Alan