Unable to perform UDim2.new in this case?

I am making parts in my game simulate a humanoid in a way. I put a health value in each part (partinstance).

When the the part's health value changes.. I put a enable the Parts "Health bar Billboard Gui". I get the health's percent by doing local percent = math.floor(Health.Value/MaxHealth*100)/100

I then use the percent variable here. "green" is the green overlay frame you usually have on health bars. The green overlay will vary in size depending on the percent of health.

green.Size = UDim2.new(percent, 0, 1, 0) 
green.Position = (UDim2.new(0, 1 - percent, 0, 0)), "Out", "Quad", 1, false, nil 

However, the only thing the script isn't doing is exactly that. My test prints stop at those lines and does not give any other errors. Am I doing this incorrectly?

Here is my hierarchy of the Billboard Gui. http://prntscr.com/7vyoc0

Here is my full script.

local MaxHealth = 100
HealthDisplay = game.ReplicatedStorage.HealthDisplay:Clone()



function AddHealthModule(partinstance)
    local Health = Instance.new("IntValue", partinstance)
    Health.Name = "Health"
    Health.Value = MaxHealth
    local display = HealthDisplay:Clone()
    display.Parent,display.Adornee = partinstance,partinstance

    local percent = math.floor(Health.Value/MaxHealth*100)/100
    local green = display.back.green


    Health.Changed:connect(function()
        local display = Health.Parent.HealthDisplay
        display.Enabled = true
        display.back.HealthTxt.Text = "Health"..Health.Value.."/"..tostring(MaxHealth)
        green.Size = UDim2.new(percent, 0, 1, 0) --Doesn't work?
        green.Position = (UDim2.new(0, 1 - percent, 0, 0)), "Out", "Quad", 1, false, nil --Neither does this
        if Health.Value <= 0 then
            partinstance:Destroy()
        elseif Health.Value > MaxHealth then
            Health.Value = MaxHealth
            display.HealthDisplay.Enabled = false       
        end
    end)
end
return AddHealthModule