Why is does this cframe door script error out?

This script errors out at line 7. Output: Workspace.Door.Script:7: Bad argument #1 to '?' (Vector3 expected, got nil)

part = script.Parent.Part
part2 = script.Parent.Part2
function move()
	for i= 0.1 ,50 do
		wait(0.1)
		b = 0.1+0.1
	part.Position = Position + Vector3.new(0,(b),0) 
	part2.Position = Position + Vector3.new(0,(b),0) 
	end
end

script.Parent.ClickDetector.MouseClick:connect(move)

try this

part.Position=part.Position+Vector3.new(0,b,0)
part2.Position = part2.Position+ Vector3.new(0,b,0) 

http://wiki.roblox.com/index.php?title=Vector3 and dont put parentheses around your variable