我正在将 JavaHelp 与 Java 桌面应用程序一起使用。该应用程序是使用 NetBeans 7 IDE 和装有 Windows 7 操作系统的 pc 开发的。我将主题文件创建为 HTML 文件、帮助集和导航文件。搜索引擎在帮助集文件中指定，如下所示：
<view>
<name>Search</name>
<label>Search</label>
<type>javax.help.SearchView</type>
<data engine="com.sun.java.help.search.DefaultSearchEngine">JavaHelpSearch</data>
</view>
但是每当我尝试在 javahelp 视图中使用搜索系统时，都会出现以下错误。
Exception while creating engine named com.sun.java.help.search.DefaultSearchEngine for view: javax.help.SearchView@fd25f2b
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at javax.help.search.MergingSearchEngine.makeEngine(MergingSearchEngine.java:166)
at javax.help.search.MergingSearchEngine.<init>(MergingSearchEngine.java:60)
at javax.help.JHelpSearchNavigator.getSearchEngine(JHelpSearchNavigator.java:110)
at javax.help.plaf.basic.BasicSearchNavigatorUI$SearchActionListener.actionPerformed(BasicSearchNavigatorUI.java:119)
at javax.swing.JTextField.fireActionPerformed(JTextField.java:508)
at javax.swing.JTextField.postActionEvent(JTextField.java:721)
at javax.swing.JTextField$NotifyAction.actionPerformed(JTextField.java:836)
at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1664)
at javax.swing.JComponent.processKeyBinding(JComponent.java:2879)
at javax.swing.JComponent.processKeyBindings(JComponent.java:2926)
at javax.swing.JComponent.processKeyEvent(JComponent.java:2842)
at java.awt.Component.processEvent(Component.java:6282)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1895)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:762)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1027)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:899)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:727)
at java.awt.Component.dispatchEventImpl(Component.java:4731)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Window.dispatchEventImpl(Window.java:2719)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:723)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:682)
at java.awt.EventQueue$3.run(EventQueue.java:680)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:696)
at java.awt.EventQueue$4.run(EventQueue.java:694)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:693)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
Caused by: java.security.InvalidParameterException
at com.sun.java.help.search.DefaultSearchEngine.<init>(DefaultSearchEngine.java:86)
请任何人向我解释这个问题以及如何解决它。