Turck,
Easiest best way rather than renaming files...
In your server, go to gmod/addons/ulx/cfg/server.ini ... open it.
Edit it's settings. I believe the first one there enables/disables motd.
Now, don't just save it. Go File, Save AS, and save it to gmod/cfg (NOT overwriting gmod/addons/ulx/cfg)
Anytime you want to change settings from then on, edit them in gmod/cfg/server.ini