Advanced GPAi1 Chapter 16 - Traffic Lights / Crates

You will find it comes up with an error "unable to find function ItemData::Create" so just grab item.cs from starter.fps and paste into starter.racing under server/scripts. Then open game.cs and before you call either the lights or the crates script do an exec("./item.cs"); which will predefine the ItemData class of which these two objects are derived. item.cs contains the ItemData::Create function.