Dropcolor is not a valid member of Model?

When i tried to run the game it alway's say Dropcolor is not a valid member of Model can someone help me please.

this is the script where i got it from and there is no error.

wait(2)
workspace:WaitForChild("PartStorage")

while true do
    wait(2.5) -- How long in between drops
    local part = Instance.new("Part",workspace.PartStorage)
    part.BrickColor=script.Parent.Parent.Parent.DropColor.Value
    part.Material=script.Parent.Parent.Parent.MaterialValue.Value
    local cash = Instance.new("IntValue",part)
    cash.Name = "Cash"
    cash.Value = 10 -- How much the drops are worth
    part.CFrame = script.Parent.Drop.CFrame - Vector3.new(0,1.6,0)
    part.FormFactor = "Custom"
    part.Size=Vector3.new(1.4, 1.4, 1.4) -- Size of the drops
    part.TopSurface = "Smooth"
    part.BottomSurface = "Smooth"
    game.Debris:AddItem(part,20) -- How long until the drops expire
end

and this is my script with the error.

wait(2)
workspace:WaitForChild("PartStorage")

while true do
    wait(2.5)
    local part = Instance.new("Part",workspace.PartStorage)
    part.BrickColor=script.Parent.Parent.Parent.DropColor.Value
    part.Material=script.Parent.Parent.Parent.MaterialValue.Value
    local cash = Instance.new("IntValue", part)
    cash.Name = "Cash"
    cash.Value = 10
    part.CFrame = script.Parent.Drop.CFrame - Vector3.new(0,1.6,0)
    part.formFactor = "Custom"
    part.Size=Vector3.new(1.4, 1.4, 1.4)
    part.TopSurface = "Smooth"
    part.BottomSurface = "Smooth"
    game.Debris:AddItem(part,20)
end