[babag]

that didn't seem to do it. this is what i have:

  elms["button_"..k] = {
    type = "Button",
    z = 1,
    x = ((k - 1) % buttons_per_row) * button_width,
    y = math.floor((k - 1) / buttons_per_row) *  button_height,
    w = button_width,
    h = button_height,
    caption = v.label,
    func = btn_click,
    params = {v.command},
    tooltip = "I'm a button"
  }

still crashes. tried also with/without comma at end of line. also tried wit parentheses instead of curly brackets.