Character is not valid of member player ?

This is most likely caused by the fact that you are not waiting for the character to load, because the player loads before the character does

Try this:

local player = game.Players.LocalPlayer
repeat wait() until player.Character

player.Character.Humanoid.Died:connect(function()
    print(player.Name.." died")
    wait(5)
    workspace.CurrentCamera.Blur.Enabled = true
    print("Load Blur")
end)