Difficulty in controling timeline with : _level1.gotoAndStop("2");

the movie thumbnail.swf loads on level 1 and has on its
timeline the mc stripmask ;

_level1.gotoAndStop(“2”); action is placed on a frame of mc stripmask
timeline ;

but the thing does not happen as planned and the movie runs out of control ;
it looks like it goes to the frame 1 in the root of level 1 and plays on and on mc stripmask ;

any hint my dear friends ?

Thank you all