Thirdup, you might have missed to enable exporting in the Config.lua file that is located in the same director as export.lua.
Or you might have introduced a syntax error when editing in the files, have you checked Ka-50/temp/error.log (path and filename from memory, might be errors.log). If there is an error in one of the lua files it will be at the bottom of that file.
Might also be a firewall problem, altough i consider that highly unlikely when udp_sender is working.