Bug in line 28?

local mon = peripheral.wrap("right")
mon.setTextScale(1)
mon.setTextColor(colors.white)
local button={}
mon.setBackgroundColor(colors.black)

function setTable(name, func, xmon, xmax, ymin, ymax)
  button[name] = {}
  button[name]["func"] = func
  button[name]["active"] = false
  button[name]["xmin"] = xmin
  button[name]["ymin"] = ymin
  button[name]["xmax"] = xmax
  button[name]["ymax"] = ymax
end

function funcName()
  print("You Clicked buttonText")
end

function fillTable()
  setTable("buttonText", funcName, 5, 25, 4, 8)
end

function fill(text, color, bData)
  mon.setBackgroundColor(color)
  local yspot = math.floor((bData["ymin"] + bData["ymax"]) /2)
  local xspot = math.floor((bData["xmax"] - bData["xmin"] - string.len(text)) /2) +1
  for j = bData["ymin"], bData["ymax"] do
    mon.setCursorPos(bData["xmin"], j)
    if j == yspot then
      for k = 0, bData["xmax"] - bData["xmin"] - string.len(text) +1 do
        if k == xspot then
          mon.write(text)
        else
          mon.write("")
        end
      end
    else
      for i = bData["xmin"], bData["xmax"] do
        mon.write("")
      end
    end
  end
  mon.setBackgroundColor(colors.black)
end

function screen()
  local currColor
  for name,data in pairs(button) do
    local on = data["active"]
    if on == true then currColor = colors.lime else currColor = colors.red end
    fill(name, currColor, data)
  end
end

function checkxy(x, y)
  for name, data in pairs(button) do
    if y>=data["ymin"] and y <= data["ymax"] then
      if x>=data["xmin"] and x<= data["xmax"] then
        data["func"]()
        data["active"] = not data["active"]
        --print(name)
      end
    end
  end
end

function heading(text)
  w, h = mon.getSize()
  mon.setCursorPos((w-string.len(text))/2+1, 1)
  mon.write(text)
end

fillTable()
while true do
  mon.clear()
  heading("Mob Control")
  screen()
  local e,side,x,y = os.pullEvent("monitor_touch")
  --print(x..":"..y)
  checkxy(x,y)
  sleep(.1)
end