I believe it’s just a typo. You declared the humrp variable as hum:FindFirstChild("HumanoidRootPart"). Obviously, HumanoidRootPart does not exist in your Humanoid, therefore it’s value is nil and does not return a CFrame
I mean the Humanoid instance itself. You used FindFirstChild, meaning you attempted to find a part named “HumanoidRootPart” inside of a Humanoid instance.