A player got this message when trying to imp a guard tower.  I'm certain I've made & imped many guard towers on 1x servers long before I reached 20 fighting.   Is this a bug, or is it a change to how things work? If it's a change, I think it makes the game unnecessarily harder on slower servers.   EDIT:  to clarify, this is on my own server.  I have not modded it so that players can't imp towers.