What does this mean?

I am trying to access ServerStorage, by going game.ServerStorage, but then the output displays 'ServerStorage is not a valid member of DataModel.' Should I not use ServerStorage for storing stuff which I clone?

Code (the variables, as they are the problem)

local ngill = game.ServerStorage.Narrowgill:Clone()

local tmple = game.ServerStorage.Temple:Clone()

local pgrounds = game.ServerStorage.Pitgrounds:Clone()

local btops = game.ServerStorage.Bricktops:Clone()

local bstn = game.ServerStorage.Bastion:Clone()

local lobby = game.ServerStorage.Lobby:Clone()

Thanks, if you can answer, it would be greatly appreciated!