如何关闭一个JApplet???急！！！请大家看看呀！！！

系统报错为！！
java.security.AccessControlException: access denied (java.lang.RuntimePermission
 exitVM)
        at java.security.AccessControlContext.checkPermission(AccessControlConte
xt.java:270)
        at java.security.AccessController.checkPermission(AccessController.java:
401)
        at java.lang.SecurityManager.checkPermission(SecurityManager.java:542)
        at java.lang.SecurityManager.checkExit(SecurityManager.java:762)
        at java.lang.Runtime.exit(Runtime.java:88)
        at java.lang.System.exit(System.java:713)
        at CC$25.actionPerformed(CC.java:410)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:17
64)
        at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(Abstra
ctButton.java:1817)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel
.java:419)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:257
)
        at javax.swing.AbstractButton.doClick(AbstractButton.java:289)
        at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1
113)
        at javax.swing.plaf.basic.BasicMenuItemUI$MouseInputHandler.mouseRelease
d(BasicMenuItemUI.java:943)
        at java.awt.Component.processMouseEvent(Component.java:5134)
        at java.awt.Component.processEvent(Component.java:4931)
        at java.awt.Container.processEvent(Container.java:1566)
        at java.awt.Component.dispatchEventImpl(Component.java:3639)
        at java.awt.Container.dispatchEventImpl(Container.java:1623)
        at java.awt.Component.dispatchEvent(Component.java:3480)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3450
)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3165)        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3095)
        at java.awt.Container.dispatchEventImpl(Container.java:1609)
        at java.awt.Component.dispatchEvent(Component.java:3480)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:450)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchTh
read.java:197)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThre
ad.java:150)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:144)        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:136)        at java.awt.EventDispatchThread.run(EventDispatchThread.java:99)