How do i make setinterval work in main MC

good day all

merry christmas and a happy new year to all

please can someone tell me how i can make a SetInterval code work for mii please this is the code am using

fastFrames = function(){ myMovie_mc.nextFrame(); updateAfterEvent(); } speedyID = setInterval(fastFrames, 40);
when i use it with for example a small animation and test the movie it works well well when i export it as a SWF file and test it again it still works BUT when i import the same swf, MC into a main MC it stops working and somehow the mc changes from a mc symbol to a graphic symbol and i aint got a clue what that means anyone who understands please help mee for chrismas sake tanks alot all i got the code from here