What does attempt to index upvalue 'Character' (a nil value) mean?

local Player=game.Players.LocalPlayer
local Character=Player.Character
local Mouse=Player:GetMouse()

Mouse.KeyDown:connect(function(K)
	if K=="q" then
		local Frog=workspace.Frog:Clone()
		Frog.Parent=workspace
		Frog.CFrame=Character.Torso.CFrame+Vector3.new(0,5,0)
		while Mouse.KeyDown:connect(function(Q)end)do
			wait(1)
			if Q=="q" then
				Frog.Size=Frog.Size+Vector3.new(.1,.1,.1)
			end
		end
		
			Mouse.Button1Down:connect(function()
		Frog.Anchored=false
		Frog.BodyPosition.position=Mouse.Hit.p
		local Debris=game:GetService("Debris")
		wait(5)
		Frog.BrickColor=BrickColor.new("Really black")
		Debris:AddItem(Frog,5)
		end)
	end
end)

This works fine until I start a server, and the output says

attempt to index upvalue 'Character' (a nil value)

what am I doing wrong? thank you in advanced