what always works for me is too uncheck an active masterfile and then recheck it then launch loot. I don't know why it works but I've had to do it multiple times when the game or a program decides my load order isn't active but nexus says it is.
The tutorial is slightly misleading, you don't use the actor alias you use the property name. So reopen your properties window in the Papyrus fragment section and use whatever you set as the property name rather than Alias.