Error 338 when starting my program

function mining()
	for a = 0, 100, 1 do
		for b = 0, 100, 1 do
			turtle.dig()  
			turtle.forward()
			
			turtle.detectUp()  -- Runs "turtle.detectUp()", but ignores the result.
			
			do  -- This gets done no matter what.
				turtle.digUp()
				sleep(0.25)
			end
		
			turtle.detectDown()  -- Runs "turtle.detectDown()", but ignores the result.

			do  -- This gets done no matter what.
				turtle.digDown()
				sleep(0.25)
			end
	
			fuel = turtle.getFuleLevel()  -- Typo; no such function.

			if(fuel < 400) then
				turtle.select(1)
				turtle.refuel()
			end
	
			turtle.select(2)
			turtle.drop(turtle.getItemCount() - 1)
			turtle.select(3)
			turtle.drop(turtle.getItemCount() - 1)
		end

		turtle.turnLeft()
		turtle.forward()
		turtle.turnLeft()

		for b = 0, 100, 1 do
			turtle.dig()  
			turtle.forward()
			
			turtle.detectUp()  -- Runs "turtle.detectUp()", but ignores the result.

			do  -- This gets done no matter what.
				turtle.digUp()
				sleep(0.25)
			end

			turtle.detectDown()  -- Runs "turtle.detectDown()", but ignores the result.

			do  -- This gets done no matter what.
				turtle.digDown()
				sleep(0.25)
			end

			if(fuel < 400) then  -- "fuel" isn't being updated...
				turtle.select(1)
				turtle.refuel()
			end

			turtle.select(2)
			turtle.drop(turtle.getItemCount() - 1)
			turtle.select(3)
			turtle.drop(turtle.getItemCount() - 1)
		end

		turtle.turnRight()
		turtle.forward()
		turtle.turnRight()
	end
end

function statusBildschirm()
	term.setCursorPos( 1, 3)
	term.clearLine()
	fuellevel = turtle.getFuelLevel()
	print("Fuel-Level: " .. fuellevel)
end

local function forward()  -- For convenience.
	while not turtle.forward() do  -- Attempt to go forward, and if it fails, loop...
		turtle.dig()
		turtle.attack()
	end
end

local function mining()
	for a = 0, 201 do
		for b = 0, 100 do  -- 101 movements per row, plus the starting block, is 102 blocks per row. Intentional, or should this only go to 99...?
			forward()

			while turtle.detectUp() do turtle.digUp() end  -- So long as blocks are above us, dig.

			if turtle.detectDown() then turtle.digDown() end  -- No need to repeat this.

			if turtle.getFuelLevel() < 400 then
				turtle.select(1)
				turtle.refuel()
			end

			for c = 2, 3 do
				if turtle.getItemCount(c) > 1 then  -- Changing slots is slow, so let's only do it if we need to.
					turtle.select(c)
					turtle.drop(turtle.getItemCount() - 1)
				end
			end
		end

		if bit.band(a,1) == 1 then  -- if "a" is an odd number, then...
			turtle.turnRight()
			forward()
			turtle.turnRight()
		else
			turtle.turnLeft()
			forward()
			turtle.turnLeft()
		end
	end
end

local function statusBildschirm()
	term.setCursorPos( 1, 3)
	term.clearLine()
	fuellevel = turtle.getFuelLevel()
	print("Fuel-Level: " .. fuellevel)
end