Java Exception Thrown

sCols = {
  a = colors.white,
  b = colors.black,
  c = colors.red,
  d = colors.blue,
  e = colors.gray,
  f = colors.lightGray,
  g = colors.brown,
  h = colors.purple,
  i = colors.orange,
  j = colors.green,
  k = colors.yellow,
  l = colors.lightBlue,
  m = colors.lime,
  n = colors.magenta,
  o = colors.pink,
}
function findCol(color)
  for k, v in pairs(sCols) do
	if v == color then
	  fCol = k
	end
  end
  return fCol
end
function drawLine(xS, yS, xF, yF, colour)
  loadScreens()
  if srcs.loaded ~= nil then
	for sY=yS, yF do
	  for start=xS, xF do
		srcs[srcs.loaded][sY][xS] = findCol(colour)
	  end
	end
  else
	local rTbl = {
	  false,
	  7,
	}
	return rTbl
  end
end
function clearScreens()
srcs = "{loaded = nil}"
saveScreens()
end
local function saveScreens()
  if dirLoadSet == nil then
	local h = fs.open("gData/screens","w")
	h.write(srcs)
	h.close()
  else
	local h = fs.open(dirLoadSet.."/screens","w")
	h.write(srcs)
	h.close()
  end
end
local function loadScreens()
  if dirLoadSet == nil then
	if not fs.exists("gData") then
	  fs.makeDir("gData")
	  local h = fs.open("gData/screens","w")
	  h.write("loaded = nil")
	  h.close()
	end
	local h = fs.open("gData/screens","r")
	scrs = textutils.unserialize(h.readAll())
	h.close()
  else
	local h = fs.open(dirLoadSet.."/screens","r")
  end
end
function setFocus(name)
  loadScreens()
  srcs.loaded = name
  saveScreens()
end
function resizeWindow(name, newW, newH)

end
function drawScreen(name, x, y)
  if name ~= "loaded" then
	loadScreens()
	  if scrs.loaded then
		if scrs[name] ~= nil then
		  for hi=1, #scrs[name] do
			for wi=1, #scrs[name][hi] do
			  for i=1, #scrs[name][hi][wi] do
				local char = string.sub(scrs[name][hi][wi], i, i)
				if i==1 then
				  paintutils.drawPixel((wi+x)-1,(hi+y)-1,sCols[char])
				elseif i==2 then
				  term.setTextColor(sCols[char])
				elseif i==3 then
				  term.setCursorPos((wi+x)-1,(hi+y)-1)
				  write(char)
				end
			  end
			end
		  end
		  local rTbl = {
			true,
			name,
		  }
		  return rTbl
		end
	  else
		local rTbl = {
		  false,
		  4,
		}
		return rTbl
	  end
  else
	local rTbl = {
	  false,
	  2,
	}
	return rTbl
  end
end
function newScreen(name, width, height)
  loadScreens()
  if name ~= "loaded" then
  scrs[name] = {}
	for h=1, height do
	  scrs[name][h] = {}
	  for w=1, width do
		scrs[name][h][w] = "abc"
	  end
	end
	saveScreens()
	local rTbl = {
	  true,
	  name,
	}
	return rTbl
  else
	local rTbl = {
	  false,
	  1,
	}
	return rTbl
  end
end

os.loadAPI("gAPI")
gAPI.newScreen("firstScreen",10,10)
gAPI.drawScreen(1,1)