Im Trying To Run A Run.Bat File To Play My Friends Runescape Private Server, When I Try To Connect However I Get This Error

Exception in thread "main" java.lang.NoClassDefFoundError: client
Caused by: java.lang.ClassNotFoundException: client
at java.net.URLClassLoad$1.run<Unknown Source>
at java.security.AccessController.doPrivileged<Native Method>
at java.net.URLClassLoader.findClass<Unknown Source>
at java.lang.ClassLoader.LoadClass<Unknown Source>
at sun.misc.Launder$AppClassLoader.loadClass<Unknown Source>
at java.lang.ClassLoader.loadClassInternal<Unknown Source>
Press any key to continue . . .


Any Idea's On How To fix This?