Experiment terminates right after the start

Online experiments
9

I did put “None” into the mask field of the consent image. I have removed it but it still does not show up on screen. It looks as follows in JS:

consent_sheet = new visual.ImageStim({
    win : psychoJS.window,
    name : 'consent_sheet', units : 'height', 
    image : undefined, mask : undefined,
    ori : 0.0, pos : [0, (((- 0.5) * (2.52 - 1)) - 0.1)], size : [1, 2.52],
    color : new util.Color([1, 1, 1]), opacity : 1.0,
    flipHoriz : false, flipVert : false,
    texRes : 128.0, interpolate : true, depth : 0.0 
  });

It is interesting though that in the corresponding definitions of the two flags, the correct file locations are specified:

adenauer = new visual.ImageStim({
    win : psychoJS.window,
    name : 'adenauer', units : undefined, 
    image : 'stimuli/bundesflagge.png', mask : undefined,
    ori : 0.0, pos : [(- 0.55), 0.45], size : [0.05, 0.025],
    color : new util.Color([1, 1, 1]), opacity : undefined,
    flipHoriz : false, flipVert : false,
    texRes : 128.0, interpolate : true, depth : -5.0 
  });
  union_jack = new visual.ImageStim({
    win : psychoJS.window,
    name : 'union_jack', units : undefined, 
    image : 'stimuli/union_jack.png', mask : undefined,
    ori : 0.0, pos : [(- 0.49), 0.45], size : [0.05, 0.025],
    color : new util.Color([1, 1, 1]), opacity : undefined,
    flipHoriz : false, flipVert : false,
    texRes : 128.0, interpolate : true, depth : -6.0 
  });

I can’t see them right now, however, because I do not know how to make the clickable polygons that I have to place in the same locations transparent. I set the opacity argument to 0 but that does not seem to do the trick.

german_switch = new visual.Rect ({
    win: psychoJS.window, name: 'german_switch', 
    width: [0.05, 0.025][0], height: [0.05, 0.025][1],
    ori: 0.0, pos: [(- 0.55), 0.45],
    lineWidth: 1.0, lineColor: new util.Color(undefined),
    fillColor: new util.Color(undefined),
    opacity: 0.0, depth: -7, interpolate: true,
  });
  
  english_switch = new visual.Rect ({
    win: psychoJS.window, name: 'english_switch', 
    width: [0.05, 0.025][0], height: [0.05, 0.025][1],
    ori: 0.0, pos: [(- 0.49), 0.45],
    lineWidth: 1.0, lineColor: new util.Color(undefined),
    fillColor: new util.Color(undefined),
    opacity: 0.0, depth: -8, interpolate: true,
  });