"Unable to cast value to object"?

while CurrentStand ~= nil do
		wait(2)
			for i,v in pairs(glowparts) do
				local glowpart = v
				local fadeOut = game:GetService("TweenService"):Create(glowpart, fadeOutInfo, {Transparency=1})
				fadeOut:Play()
				print("fadeOut completed")
			end
			wait(.7)
			for i,v in pairs(glowparts) do
				local glowpart2 = v
				local fadeIn = game:GetService("TweenService"):Create(glowpart2, fadeInInfo, {Transparency=0})
				fadeIn:Play()
				print("fadeIn completed")
			end
	wait(math.random(1,3))
end