EDIT: Its a level up system, and when a player levels up this happens.
I have the level up script somewhere else, this part just won't work. :P
player = game.Players.LocalPlayer
local fireworks = Instance.new("Part")
fireworks.Shape = 0
fireworks.formFactor = "Symmetric"
fireworks.Size = Vector3.new(1,1,1)
fireworks.BrickColor = BrickColor.Random()
fireworks.CFrame = player.Character.Head.CFrame + Vector3.new(0,2,0)
fireworks.Parent = game.Workspace
game:GetService("Debris"):AddItem(fireworks, 2)
fireworks.Velocity = Vector3.new(math.random(-30,30),math.random(-30,30),math.random(-30,30))

2 comments
Error messages?
Try 'player.Character.Head.Position' instead of using 'player.Character.Head.CFrame'.