[Lua] [Error] attempt to call nil

I've recently started futzing about with ComputerCraft, since my server is doing a for fun feed the beast server for admins and trusted players. I decided it would be pretty cool to have a tower surrounded by a canyon, and deploy turtles to greet anyone entering and prompt them for the entry password after they press the doorbell. For the program of the greeting turtle, I can get as far as responding to the redstone signal before getting an error. The code is written here.


rednet.open("right")
signal = redstone.getInput("top")
if signal == true then
turtle.forward()
end
while not turtle.detectDown() do
turtle.foward()
end
turtle.left()
turtle.clear()
turtle.setCursorPos(1,1)
turtle.write("Welcome to the lab! Password: ")
local input = read ("*")
turtle.clear()
turtle.setCursorPos(1,1)
turtle.write("Wait here while I check!")
sleep(5)
turtle.right()
turtle.backward()
while not turtle.detectDown() do
turtle.backward()
end
rednet.broadcast(input)

Split into new topic.

I think you've confused your APIs here. You have a bunch of turtle calls with functions found in the term API. Try switching all of the term calls over to actually call from term.

What error are you getting?
And it's not

turtle.backward()

It's

turtle.back()

--Other Moving Stuff
turtle.down()
turtle.up()
turtle.turnLeft()
turtle.turnRight()

--[[
This Was Also
Wrong..
]]--
turtle.clear() --Should be term.clear()
turtle.setCursorPos(1,1) --Should be term.setCursorPos(1,1)

rednet.open("right")
signal = redstone.getInput("top")
if signal then
turtle.forward()
end

while not turtle.detectDown() do
turtle.forward()
end

turtle.turnLeft()
term.clear()
term.setCursorPos(1,1)
write("Welcome to the lab! Password: ")
local input = read ("*")
term.clear()
term.setCursorPos(1,1)
write("Wait here while I check!")
sleep(5)
turtle.turnRight()
turtle.back()
while not turtle.detectDown() do
turtle.back()
end
rednet.broadcast(input)