[Q] Error when runing flashtool topic

Please can any one help with this error...log


java.lang.ClassNotFoundException: gui.Main
at java.net.URLClassLoader.run(Unknown Source)
at java.net.URLClassLoader.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.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.exe4j.runtime.LauncherEngine.launch(Unknown Source)
at com.exe4j.runtime.WinLauncher.main(Unknown Source)

I'm using windows 8.1 and I installed java+ java jdk