This error is mostly because of the jar not being positioned into the jar folder, the forge.jar not being named to custom.jar, or the file was corrupted whereas uploading. Confirm that the folder is inside of the jar folder and if it isn't, reupload it through FileZilla or another FTP program. It's best to do the same when working in your server by downloading its information from the server FTP. Be sure if you happen to do this, you're confirming that the model is similar for the modpack. This server is hosted and staffed by many gamers from the original F/A server, so we can simply talk with our participant base as a result of we used to be members of that very same player base. You'll be able to put resource packs in, or really even random mod recordsdata that don't go within the configs or mods folder. Creating modpacks with this launcher is super straightforward: 1 solely drag & drop of configs and mods right into a folder, 2 ZERO!