The problem could be if you just talking about client files is: The server owner hasn't updated the mod to the server while the mod updated and you're running a newer version that the server hasn't updated to. the only things you can do in this situation is if you have the old build of my mod that you can load manually. Also you could make the server owner/admins aware if they aren't already of the new update so you and everyone else can join then. Hopefully you can get back to playing soon. Pce.