SetSignLines does not work

[xoft]

You'd need to make an array out of the "lines" variable. Lua has bit different syntax rules:

local a, b, c = 1, 2, 3, 4
--> a == 1; b == 2; c == 3; 4 gets forgotten

-- In this same fashion:
local lines = "line1", "line2", "line3", "line4"
--> lines = "line1"; Lua discards "line2" - "line4"

-- You probably want this:
local lines = { World:GetSignLines(PosX, PosY, PosZ) }
--> lines[1] == "line1"; lines[2] == "line2" etc.