why does it want an extra end?

[Twitchi 0]

Hey guys, I have been learning Lua recently and have ran into a bit of an issue, every time I try to run the code bellow I get an error (missing end to close function) but no matter how many times I look at it, I see an end closing the function..
I'm sure I have made a massive error I just can't see it for all the looking

 

function walk()
  local clear = robot.detect()
    if clear == true then       -- if block forward
        while clear == true do -- while it is true
        local upClear = robot.detectUp()
          if upClear == true then
            robot.up()           -- fly up
            clear = robot.detect()--check forward again
          else if upClear == false then
            clear = false
          end --upclear
        end --while
    end --block forward
  robot.forward()   --no obstical move forward

    local clearDown = robot.detectDown()  --Check for ledge
      while clearDown == false do
        robot.down()
        clearDown = robot.detectDown()
      end -- while
end -- function

any help is much appreciated as no amount of googling can find me an answer

also full paste if needed http://pastebin.com/5MEB99V5

[TYKUHN2 2]

elseif instead of else if. As it is it's two statements and wants two ends.

[Twitchi 0]

Thank you so very much

totally the type of thing I would never have seen myself