Helo Maarten,   There's some coding error in SL_G1000.lua in line 26 (missing bracket ')' ):   -- "Slave Server" example LUA plug-in, by Pete Dowson, October 2009 -- To make the Server FS act as a slave, following the Client FS acting as Master   -- The SOCKET module is built into FSUIPC, but is not active until "required" local socket = require("socket")   -- Set the host name to the name of the PC running this Server local host = "localhost"   -- The port must match the port selected in the client and not clash with others. local port = "34568"     local function processdata(data) -- decode string, format is lvarname,lvarvalue,isstring (0 or 1) local index1 = 1 local index2 = string.find(data, ",") local lvarname = string.sub(data, index1, index2 - 1) index1 = index2 + 1 index2 = string.find(data, ",", index1) local lvarvalue = string.sub(data, index1, index2 - 1) local lvarisstring = string.sub(data, index2 + 1)   if lvarisstring == "1" then for i = 1, 6 do if (string.len(lvarvalue) >= i then             ////here exactly - error when parsing/// ipc.writeLvar("SLX_StringValue" .. i, string.byte(lvarvalue, i) else ipc.writeLvar("SLX_StringValue" .. i, 0) end end else ipc.writeLvar("SLX_" .. lvarname, tonumber(lvarvalue)) end ipc.writeLvar("SLX_" .. lvarname .. "_Set", 1) end   local server = assert(socket.bind(host, port)) local ack = "<EOF>" while 1 do     print("slx_fs9gps_server: waiting for client connection...")     local control if (server ~= nil) control = server:accept() else control = nil     if control ~= nil then print("slx_fs9gps_server: client connected!") while 1 do  local data = control:receive() if data == nil then print("slx_fs9gps_server: client disconnected") -- ipc.control(65794) -- Pause FS break end else local index = string.find(data, "<EOF>") if index ~= nill then  data = string.sub(data, 1, index - 1) if data == "ping" then assert(control:send("ping<EOF>")) else assert(control:send(ack))       processdata(data) end end end end     end end   Best wishes, Darek