I discovered that this mod is not compatible with Updated Construction Drones.

It throws this error then placing any wall:
Updated_Construction_Drones::on_script_path_request_finished (ID 116)
The mod Alien Walls (0.9.14) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event AlienWall::script_raised_revive (ID 80)
AlienWall/control.lua:127: attempt to index local 'entity' (a nil value)
stack traceback:
AlienWall/control.lua:127: in function 'on_hybrid_built'
AlienWall/control.lua:248: in function <AlienWall/control.lua:248>
stack traceback:
[C]: in function 'revive'
...ated_Construction_Drones__/script/construction_drone.lua:1391: in function <...ated_Construction_Drones__/script/construction_drone.lua:1366>
(...tail calls...)
...ated_Construction_Drones__/script/construction_drone.lua:2063: in function 'handler'
core/lualib/event_handler.lua:47: in function <core/lualib/event_handler.lua:45>

I looked into it and was able to fix it easily:
control.lua:125 add at the beginning of function on_hybrid_built(entity) this:

if (entity == nil) then
return;
end

It fixed this problem