ActionScript 2.0 :: Advancing MovieClip Frames Forward / Backward

I would like to control the embedded video by advancing the playhead forward and /or backward by increments > 1 frame. I have tried:

on (press) {
stop();
for(var j = 0; j < 4; j++)
nextFrame();
}
- and -
on (press) {
stop();
mc.gotoAndStop(mc._currentframe + 4);
} (mc = movie clip)

I enabled Simple Buttons and clicked on the buttons containing the AS; they are not functioning. Although, the play, stop, goto first and last frame buttons work. I am perplexed. I have tried creating a new .fla file with a different .wmv, and the failure to function persists.