problems in terminal when trying to re-enable java 6 for runescape

whenever i try to dot the third step in sudo which is in terminal "sudo mv /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin /Library/Internet\ Plug-Ins/disabled" the terminal comes back with "mv: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin: No such file or directory" i do not know any other way to enable java 6 and because java 7 is still unstable on chrome i do not know what to do