Trouble playing movie from directory of jpegs

1

I have been trying to make a self-playing animation of stillframes dumped into a folder. The first frame loads, but the movie never advances to the next frame, no matter whether I use loadMovie or the movieClipLoader method. not even a nextFrame in keyframes produces a result. Clearly I am overlooking (or have forgotten) something very basic. what would you suggest I look for, fellow as2’ers?