Flash CS4 ActionScript help (Falling Snow)

Hi guys I have just been following the Falling snow tutorial http://www.kirupa.com/developer/flashcs4/falling_snow_as3_cs4_pg1.htm

I have managed to get it working and the snow is near the end of my animation for about 100 frames, however I cant get it to stop snowing when I test out my animation. The animation loops as usual but after the first loop it snows throughout the whole animation, not just the last frames.

Any help please???

:garfield: