You don't need to use gotoAndStop. Just stop(); will do. The following will stop the movieclip on rollover:
PHP Code:
blue_mc.buttonMode=true;
blue_mc.addEventListener(MouseEvent.ROLL_OVER, mcOver, false, 0, true);
function mcOver(e:MouseEvent):void {
blue_mc.stop();
}
If you want it to stop and then start again the next time it is rolled over you need to test to see if the movie is playing or not using an if statement.
PHP Code:
var mcplaying:Boolean = true;
blue_mc.buttonMode=true;
blue_mc.addEventListener(MouseEvent.ROLL_OVER, mcOver, false, 0, true);
function mcOver(e:MouseEvent):void {
if (mcplaying == true) {
blue_mc.stop();
mcplaying = false;
} else {
blue_mc.play();
mcplaying = true;
}
}