How do I fix this script?

It's a crushing ceiling script I came upon, and I was wanting to use it, but it's broken. Anyway to fix it?

\Lava = script.Parent.Parent.Lava <- Area where it is broken.
LavaVelocity = Lava.BodyVelocity <- Here too.

while true do
LavaVelocity.velocity = Vector3.new(0,1,0)
wait(1)
LavaVelocity.velocity = Vector3.new(0,0,0)
wait(1)
LavaVelocity.velocity = Vector3.new(0,-200,0)
wait(1)
LavaVelocity.velocity = Vector3.new(0,0,0)
wait(1)
end