Help with Lua plugin!

[gran.torino]

im newbie on LUA and i was looking for a plugin that auto reply when you are away, i just found a script by SIlentstorm

local function onTextMessageEvent(serverConnectionHandlerID, targetMode, toID, fromID, fromName, fromUniqueIdentifier, message, ffIgnored)
    local  response = "You managed to send me a private Message"
    if targetMode = ts3defs.TextMessageTargetMode.TextMessageTarget_CLIENT then
        ts3.requestSendPrivateTextMsg(serverConnectionHandlerID, response, fromID)
    end
end 

but it didnt work, maybe i did something wrong testing. I create a folder called "reply" in plugins/lua_plugins*
then inside create a file called init.lua and paste the script, then i reloaded the plugin, but didnt work, can anyone help me please?