Getting an error 'end expected'?

Hello, an "end" is expected to close the if at line 15. Your code shoud be:

-- STAGE 2
local dialogGui = script.Parent
--local ReplicatedStorage = game:GetService("ReplicatedStorage")
local object = script.Parent
local host = workspace.Host
local guiObject = script.Parent
local myThread = coroutine.running()

-- Local type writer
function localTypeWriter(textElement, goal)
    for i=1, string.len(goal), 1 do
        textElement.Text = string.sub(goal,1,i)
        wait(.2)
    end
end

function continueDialog()
    coroutine.resume(myThread)
end

host.Touched:Connect(continueDialog)
workspace.host.Touched:Connect(function(hit) -- Missing end for this function
    if hit.Parent:findFirstChild("Humanoid") then -- Missing end for this if
        guiObject.Visible = true

        -- Require module
        --local TypeWriter = require(ReplicatedStorage:WaitForChild("TypeWriter"))
        --coroutine.yield()
        -- Ajust the wait values to fit your time.
        wait(1)
        localTypeWriter(script.Parent, "Head on over to the Potion Class!")
        wait(1)
        localTypeWriter(script.Parent, "Hello there students my name is Professor Herbert")
        wait(1)
        localTypeWriter(script.Parent, "Would you like to help me create my newest Potion?")
        wait(1)
        localTypeWriter(script.Parent, "Great! I’ll need the following ingredients..")
        wait(1)
        localTypeWriter(script.Parent, "They should all be hidden somewhere within the classes go look!")
        wait(1)


        object.AnchorPoint = Vector2.new(0, 0)
        object.Position = UDim2.new{0, 0},{0, 0}


        object:TweenPosition(UDim2.new(0, 0, -10.04, 0), Enum.EasingDirection.In, Enum.EasingStyle.Sine,0.5)

        wait(2)

        script.parent.Visible = false
        if script.parent.Visible == false then 
            print("Worked!")
        end
    end -- Line added
end) -- Line added

Or maybe your are missing the end for the if at line 45.

Some identation should help you next time ;)